Home Normalized solutions for the double-phase problem with nonlocal reaction
Article Open Access

Normalized solutions for the double-phase problem with nonlocal reaction

  • Li Cai and Fubao Zhang EMAIL logo
Published/Copyright: July 25, 2024

Abstract

In this article, we consider the double-phase problem with nonlocal reaction. For the autonomous case, we introduce the methods of the Pohozaev manifold, Hardy-Littlewood Sobolev subcritical approximation, adding the mass term to prove the existence and nonexistence of normalized solutions to this problem. For the nonautonomous case, we show the existence of normalized solutions to the double-phase problem by using the Pohozaev restrict method and describing the relationship between the energy of this problem and its limit problem. Moreover, we study the existence of normalized solutions to the double-phase problem involving double Hardy-Littlewood-Sobolev critical exponents.

MSC 2010: 35A15; 35B09; 35J92

1 Introduction and preliminary results

In this article, we are concerned with the solutions of the following double-phase problem

(1.1) Δ p u Δ q u + V ( x ) ( u p 2 u + u q 2 u ) + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u l ) u l 2 u , in R N

with the normalized constraint

S c u E : R N u p d x = c p ,

where 1 < p < q < N , Δ i u = div ( u i 2 u ) , with i { p , q } , is usual i -Laplace operator, V ( x ) 0 is a C 2 function, 1 < p α ( N + α ) p 2 N < l p α ( N + α ) p * 2 N , p * N p N p , γ , μ > 0 , E W 1 , p ( R N ) W 1 , q ( R N ) , the mass constant c > 0 , the frequency λ R is unknown and appears as Lagrange multiplier, and I α is the Riesz potential of order α ( 0 , N ) defined by

I α = A ( N , α ) x N α with A ( N , α ) = Γ N α 2 π N 2 2 α Γ α 2

for each x R N \ { 0 } .

The study of equation (1.1) is motivated by recent fundamental progress in the mathematical analysis of many nonlinear patterns with unbalanced growth and nonlocal reaction. The main novelty of (1.1) is the combination of a double-phase operator and two nonlocal Choquard reaction terms. Since equation (1.1) is closely concerned with unbalanced double-phase problems and nonlocal Choquard problems. We briefly introduce in what follows the related background and applications and recall some pioneering contributions in these fields. Problem (1.1) combines an interesting phenomenon that the operator involved in (1.1) is the so-called double-phase operator whose behavior switches between two different elliptic situations, which generates a double-phase associated energy. Originally, the idea to treat such operators comes from Zhikov [61] who introduced such classes to provide models of strongly anisotropic materials, see also the monograph of Zhikov et al. [62]. We refer to the remarkable works initiated by Marcellini [37,38], where the author investigated the regularity and existence of solutions of elliptic equations with unbalanced growth conditions. We also mention the recent paper by Mingione and Rădulescu [39], which is a comprehensive overview of the recent developments concerning elliptic variational problems with nonstandard growth conditions and related to different kinds of nonuniformly elliptic operators.

The double-phase problem (1.1) is motivated by numerous models arising in mathematical physics. For instance, we can refer to the following Born-Infeld equation [11] that appears in electromagnetism:

div u ( ( 1 2 u 2 ) ) 1 2 = h ( u ) in Ω .

Indeed, by the Taylor formula, we have

( 1 x ) 1 2 = 1 + x 2 + 3 2 2 2 x 2 + 5 ! ! 3 ! 2 3 x 3 + + ( 2 n 3 ) ! ! ( n 1 ) ! 2 n 1 x n 1 + for x < 1 .

By taking x = 2 u 2 and adopting the first-order approximation, we obtain the double problem for p = 4 and q = 2 . Moreover, the n th-order approximation problem is driven by the multiphase differential operator

Δ u Δ 4 u 3 2 Δ 6 u ( 2 n 3 ) ! ! ( n 1 ) ! Δ 2 n u .

We also refer to the following fourth-order relativistic operator

u div u 2 ( 1 u 4 ) 3 4 u ,

which describes large classes of phenomena arising in relativistic quantum mechanics. Again, by Taylor’s formula, we have

x 2 ( 1 x 4 ) 3 4 = x 2 + 3 x 6 4 + 21 x 10 32 + .

This shows that the fourth-order relativistic operator can be approximated by the following autonomous double-phase operator

u Δ 4 u + 3 4 Δ 8 u .

For more details on the physical background and other applications, we refer the readers to Bahrouni et al. [6] (for phenomena associated with transonic flows) and to Benci et al. [9] (for models arising in quantum physics).

In the past few decades, the double-phase problem has been the subject of extensive mathematical studies. Using various variational and topological arguments, many authors studied the existence and multiplicity results of nontrivial solutions, ground state solutions, nodal solutions, and some qualitative properties of solutions, respectively, such as [21,43,46] in case of bounded domains. In this classical setting, we recall the seminal papers by Ni and Wei [44], Li and Nirenberg [29], del Pino and Felmer [18], del Pino et al. [19], and Ambrosetti and Malchiodi [5]. The regularity, existence of solutions, and multiplicity of the double-phase problem on the whole space can be found in [3,24,58]. The qualitative and asymptotic analysis of solutions for some related elliptic problems can refer to [13,14,28,47,60].

The second interesting phenomenon in equation (1.1) is the appearance of Choquard reaction terms, which generate the nonlocal characteristic. The nonlocal problem goes back to the description of the quantum theory of a polaron at rest by Pekar in [48] and the modeling of an electron trapped in its own hole in the work of Choquard, as a certain approximation to Hartree-Fock theory of one-component plasma [30]. In some particular cases, the Choquard equation is also known as the Schrödinger-Newton equation, which was introduced by Penrose in his discussion on the selfgravitational collapse of a quantum mechanical wave function [49]. The existence and qualitative properties of ground state solutions of Choquard equation have been widely studied in the last decades. See, for example, [32,35,4042].

Recently, physicists are often interested in the existence of normalized solutions. Indeed, prescribed mass appears in nonlinear optics and the theory of Bose-Einstein condensates, see [20,36] and the references, therein. In particular, when p = q = 2 , V ( x ) 0 , problem (1.1) is reduced to the following well known Choquard type equation:

(1.2) Δ u + λ u = ( I α * u 2 ) u , in R N .

Cazenave and Lions in [16] proved the existence and stability of normalized solutions for (1.2) with N = 3 and α = N 1 by considering the following minimizing problem:

ϑ c inf 1 2 R N u 2 d x 1 4 R N R N u ( x ) 2 u ( y ) 2 x y d x d y : u S ˜ c ,

where S ˜ c u H 1 ( R N ) : R N u 2 d x = c . In such case, we remark that (1.2) is a mass-subcritical minimizing problem, and essentially all results of (1.2) can be extended to the general case where N 3 and N 2 < α < N . While if 0 < α < N 2 , (1.2) becomes mass-supercritical and ϑ c = has no minimizers. Luo in [34] proved the existence of unstable ground state normalized solution for (1.2) with N 3 and 0 < α < N 2 by considering a constrained minimizing problem on a suitable submanifold of S ˜ c . For the following general Choquard equation:

(1.3) Δ u + λ u = ( I α * u m ) u m 2 u , in R N ,

where N 1 , α ( 0 , N ) and m N + α N , N + α ( N 2 ) + . Here, ( N 2 ) + = N 2 if N 3 , and ( N 2 ) + = 0 if N = 1 , 2 . Li and Ye in [27] studied the existence of normalized solutions for (1.3) with α ( 0 , N ) and m N + α + 2 N , N + α ( N 2 ) + by using a minimax theorem developed by Bellazzini et al. in [8]. Moreover, Ye in [56] obtained the existence of ground state normalized solution for (1.3) with a trapping potential and m = N + α + 2 N . In [15], Cao et al. focused on the existence of normalized solutions to the following equation with van der Waals type potentials:

(1.4) Δ u + λ u = μ ( I α * u 2 ) u + ( I β * u 2 ) u , in R N

under the normalized constraint S ˜ c . Compared with the well-studied case α = β , the solution set of (1.4) with different widths of two body potentials α β is much richer. Under different assumptions on c , α and β , they proved the existence, multiplicity, and asymptotic behavior of solutions to (1.4) In addition, the stability of the corresponding standing waves for the related time-dependent problem is discussed. In particular, when β = N 4 and N 5 , Jia and Luo in [25] showed some existence, nonexistence, multiplicity, and asymptotic results of normalized solutions to (1.4). These results are a continuation of works in [15]. Moreover, Yao et al. in [55] studied the following Choquard equations with lower critical exponent and a local perturbation

(1.5) Δ u + λ u = γ ( I α * u α N + 1 ) u α N 1 u + μ u q 2 u , in R N .

They proved several nonexistence and existence results by introducing some new arguments. In particular, they first considered the existence of normalized solutions to (1.5) involving double critical exponents and described some qualitative properties of the solutions with prescribed mass and of the associated Lagrange multipliers λ .

On the other hand, when 1 < p = q < N , V ( x ) 0 , the Choquard term is replaced by u l 2 u , there are few results on the following p -Laplacian equation:

(1.6) Δ p u = λ u p 2 u + u l 2 u .

In particular, when u l 2 u is g ( x , t ) with g ( x , t ) is L p -subcritical in the sense that,

lim t + g ( x , t ) t p ˆ 1 = 0

holds uniformly for x R N , where p ˆ p 2 N + p . Li and Yan [26] obtained the existence of normalized ground state solutions. In [23], Gu et al. proved the existence of normalized ground state solutions with a trapping potential for (1.6) in case of l = p ˆ . Recently, Zhang and Zhang [60] considered the following p -Laplacian equation with a L p -norm constraint:

(1.7) Δ p u = λ u p 2 u + μ u q 2 u + g ( u ) , x R N , R N u p d x = a p ,

where N > 1 , a > 0 , 1 < p < q p ˆ , μ R , g C ( R , R ) . Assume that g is odd and L p -supercritical. When q < p ˆ and μ > 0 , using Schwarz rearrangement and Ekeland variational principle, they proved the existence of positive radial ground states for suitable μ . When q = p ˆ and μ > 0 or q p ˆ and μ 0 , with an additional condition of g , they proved a positive radial ground state if μ lies in a suitable range by the Schwarz rearrangement and minimax theorems. Via a fountain theorem type argument, with suitable μ R , they showed the existence of infinitely many radial solutions for any N 2 and the existence of infinitely many nonradial sign-changing solutions for N = 4 or N 6 . In addition, Baldelli and Yang in [7] were concerned with the existence of normalized solutions to the following ( 2 , q ) -Laplacian equation in all possible cases according to the value of p with respect to the L 2 -critical exponent 2 1 + 2 N :

(1.8) Δ u Δ q u = λ u + u p 2 u , x R N , R N u 2 d x = c 2 .

In the L 2 -subcritical case, they studied a global minimization problem and obtained a ground state solution. While in the L 2 -critical case, they proved several nonexistence results, extended also in the L q -critical case: p = q 1 + 2 N . For the L 2 -supercritical case, they derived a ground state and infinitely many radial solutions.

Inspired by the aforementioned literature, we want to study the normalized solutions of the double-phase problem with nonlocal reaction (1.1).

The features of equation (1.1) are the following:

  1. The presence of several differential operators with different growth, which generates a double-phase associated energy.

  2. The equation combines the multiple effects generated by two nonlocal terms and a variable potential.

  3. Due to the unboundedness of the domain, the Palais-Smale sequence does not have the compactness property.

Throughout this article, for any m [ 1 , ) , L m ( R N ) is the usual Lebesgue space endowed with the norm

u m R N u m d x 1 m ,

and W 1 , i ( R N ) ( i { p , q } ) is the usual Sobolev space endowed with the norm

u W 1 , i ( R N ) R N u i d x + R N u i d x 1 i .

For equation (1.1), we introduce the working space E endowed with the norm

u E u W 1 , p ( R N ) + u W 1 , q ( R N ) .

In addition, for given u E \ { 0 } and t > 0 , we define the scaling function:

u t t N p u ( t x ) ,

which remains in E and preserves the L p norm when t > 0 varies. E r { u E : u ( x ) = u ( x ) } .

To study equation (1.1) variationally, we give the following Hardy-Littlewood-Sobolev inequality and the Gagliardo-Nirenberg inequality.

Lemma 1.1

[31] Let t , r > 1 and 0 < α < N with 1 t + N α N + 1 r = 2 , f L t ( R N ) , and h L r ( R N ) . There exists a sharp constant C ( t , N , α , r ) , independent of f , h , such that

(1.9) R N R N f ( x ) h ( y ) x y N α d x d y C ( t , N , α , r ) R N f ( x ) t d x 1 t R N h ( x ) r d x 1 r .

If t = r = 2 N N + α , then

C ( t , N , α , r ) = π N α 2 Γ N 2 N α 2 Γ N N α 2 Γ N 2 Γ ( N ) 1 + N α N .

In this case, there is equality in (1.9) if and only if h ( const . ) f and

(1.10) f ( x ) = C ˆ ε ε 2 + x y 2 N + α 2

for some given constants C ˆ R , y R N , and ε ( 0 , + ) .

Remark 1.2

In particular, if F ( t ) = t ν for some ν > 0 . By Hardy-Littlewood-Sobolev inequality,

R N R N F ( u ( x ) ) F ( u ( y ) ) x y N α d x d y

is well defined if F ( u ) L s ( R N ) for s > 1 defined by

2 s + N α N = 2 .

Then for W 1 , p ( R N ) , we require that s ν [ p , p * ] , which implies that

p α ν p α .

Thus, power p α is called Hardy-Littlewood-Sobolev lower critical exponent and power p α is called Hardy-Littlewood-Sobolev upper critical exponent. Combining (1.9), we denote

(1.11) S α inf u E \ { 0 } R N u p d x R N ( I α * u p α ) u p α d x 1 p α > 0 .

Lemma 1.3

[1] Let N > p . There exists a constant S > 0 such that, for any u D 1 , p ( R N ) ,

u p * p S 1 u p p .

Moreover, W 1 , p ( R N ) is embedded continuously into L m ( R N ) for any m [ p , p * ] and compactly into L l o c m ( R N ) for any m [ 1 , p * ) .

Remark 1.4

By applying Lemmas 1.1 and 1.3, we see that

(1.12) S α inf u E \ { 0 } R N u p d x R N ( I α * u p α ) u p α d x 1 p α > 0 .

Lemma 1.5

[3] The space E is embedded continuously into L m ( R N ) for m [ p , q * ] and compactly into L l o c m ( R N ) for m [ 1 , q * ) .

Lemma 1.6

[2,45] The following results hold:

  1. For every m ( p , p * ) , there exists a sharp constant C ¯ N , m > 0 such that

    (1.13) u m C ¯ N , m u p δ ¯ m u p 1 δ ¯ m , u W 1 , p ( R N ) ,

    where δ ¯ m N p N m .

  2. Let 1 < q < N and 1 p < m < q * . Then there exists a sharp constant K ¯ N , m > 0 such that

    (1.14) u m K ¯ N , m u q γ ¯ m u p 1 γ ¯ m , u E ,

    where γ ¯ m N q ( m p ) m [ N q p ( N q ) ] .

Based on the aforementioned facts, we shall consider the existence and nonexistence of normalized solutions to equation (1.1). It is well known that the normalized solution of equation (1.1) can be obtained by looking for a critical point of the following functional I V , l : E R defined by

I V , l ( u ) 1 p R N u p d x + 1 q R N u q d x + R N V ( x ) 1 p u p + 1 q u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x

constrained on S c , where the potential conditions that ensure that the potential term is well defined will be given in the following argument. In addition, combining Lemmas 1.1 and 1.6, we find that

(1.15) R N ( I α * u ν ) u ν d x C N , ν , α R N u p d x 2 ν δ ν p R N u p d x 2 ν ( 1 δ ν ) p

and

(1.16) R N ( I α * u ν ) u ν d x K N , ν , α R N u q d x 2 ν γ ν q R N u p d x 2 ν ( 1 γ ν ) p

for some positive constants C N , ν , α , K N , ν , α , where δ ν N p N + α 2 ν and γ ν N q ν 2 N N + α p ν 2 N N + α [ N q p ( N q ) ] . Then on the basis of (1.15) and (1.16), we know that p ¯ N q + p q + p α 2 N is L p -critical exponent for equation (1.1).

Next, we define the ground state in the following sense.

Definition 1.1

We say that u is a ground state of equation (1.1) if it is a solution of equation (1.1) having minimal energy among all the solutions:

I V , l S c ( u ) = 0 and I V , l ( u ) = inf { I V , l ( v ) : I V , l S c ( v ) = 0 , v S c } .

In addition, when the functional I V , l is bounded from below on S c , we shall give some results about the minimization problem

a c inf u S c I V , l ( u ) .

In order to search for critical points of I V , l restricted to S c , we shall use the Pohozaev manifold P c V , l as a natural constraint of I V , l that contains all the critical points of I V , l restricted to S c , where

P c V , l { u S c : P V , l ( u ) = 0 } ,

P V , l ( u ) R N u p d x + ( δ ¯ q + 1 ) R N u q d x + δ ¯ q R N V ( x ) u q d x 1 p R N W ( x ) u p d x 1 q R N W ( x ) u q d x 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x

and W ( x ) V ( x ) , x . Moreover, we define m c V , l inf u P c V , l I V , l ( u ) .

First, we study the existence and nonexistence of normalized solutions to equation (1.1) in case of V ( x ) 0 . Hence, inspired by [17] and [50], we define the fibering map t ( 0 , ) Ψ u l ( t ) I 0 , l ( u t ) given by

Ψ u l ( t ) t p p u p p + t q ( δ ¯ q + 1 ) q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l t 2 l N p ( N + α ) p R N ( I α * u l ) u l d x .

Obviously, for any u S c , the dilated function u t belongs to the constraint manifold P c 0 , l if and only if t R is a critical value of the fibering map t ( 0 , ) Ψ u l ( t ) , that is, ( Ψ u l ) ( t ) = 0 . Thus, it is natural to split P c 0 , l into three parts corresponding to local minima, local maxima, and points of inflection. From [52], we define

( P c 0 , l ) + { u S c : ( Ψ u l ) ( 1 ) = 0 , ( Ψ u l ) ( 1 ) > 0 } , ( P c 0 , l ) 0 { u S c : ( Ψ u l ) ( 1 ) = 0 , ( Ψ u l ) ( 1 ) = 0 } , ( P c 0 , l ) { u S c : ( Ψ u l ) ( 1 ) = 0 , ( Ψ u l ) ( 1 ) < 0 } .

Now we state our main results about the autonomous problem as follows.

Theorem 1.7

Assume that γ , μ > 0 , p α < l < p ˜ p ( p + N + α ) 2 N , and V ( x ) 0 . If q < 2 p α and S α p α 2 p α p c ( p 2 ) p α , then the infimum

a c < γ 2 p α S α 2 p α p c 2 p α

is attained by u S c with the following properties:

  1. u is a positive function in R N , which is radially symmetric and nonincreasing.

  2. u is a ground state of (1.1) with some λ > q γ 2 p α S α 2 p α p c 2 p α .

Remark 1.8

To prove that a c is achieved, we need to introduce the compactness principle in [33]. However, compared with [55], due to the influence of double-phase operator and Hardy-Littlewood-Sobolev lower critical exponent, it is difficult to make an estimate on the properties of a c in advance. To overcome this difficulty, we shall give the description between S α and c in detail.

Next, we make most of Pohozaev equality, Hardy-Littlewood-Sobolev inequality, and Gagliardo-Nirenberg inequality (1.16) about the nonlocal Choquard term, we give the following nonexistence result.

Theorem 1.9

Assume that γ > 0 , l = p ¯ , and V ( x ) 0 . If

0 < μ 2 p ¯ p ( δ ¯ q + 1 ) [ 2 p ¯ N p ( N + α ) ] K N , p ¯ , α c 2 p ¯ ( 1 γ p ¯ ) ,

then equation (1.1) has no solution for any λ R .

Theorem 1.10

Assume that γ , μ > 0 , p ¯ < l < p α , and V ( x ) 0 . Then there exists c ˇ > 0 such that for every 0 < c < c ˇ , equation (1.1) has a ground state u , which is positive, radially symmetric and nonincreasing in R N with some λ R N satisfying

λ > δ ¯ q 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] q 2 l γ l q c 2 l ( 1 γ l ) q + p ( 2 l γ l q ) 2 l γ l q ,

where

c ˇ 2 p α γ S α p α 2 l γ l q ( 2 l γ l q ) p p α + 2 q l ( 1 γ l ) 1 q ( δ ¯ q + 1 ) p 2 l N p ( N + α ) 2 l γ l q ( 2 l γ l q ) p p α + 2 q l ( 1 γ l ) 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] q p p α ( 2 l γ l q ) + 2 q l ( 1 γ l ) .

Remark 1.11

To show the existence of normalized solutions to equation (1.1) with V ( x ) 0 in L p -supercritical case, we use the minimax method introduced in [17] to construct a Palais-Smale sequence. But because of the double-phase operator and Hardy-Littlewood-Sobolev low critical exponent, we need to rely on the Pohozaev manifold method to overcome the lack of compactness.

Theorem 1.12

Assume that μ > 0 , l = p α . If c , γ satisfy

0 < c < min { c ˇ , ć }

and

γ α p + α 2 p α p p S α 2 p α p ( S α ) p α ( 2 p α p ) p ( p α 1 ) μ 2 p α p p ( p α 1 ) ,

then there exists μ ˜ > 0 large enough such that for every μ > μ ˜ , equation (1.1) has a ground state u for some λ > 0 , which is positive, radially symmetric, and nonincreasing in R N , where c ˇ is introduced in Theorem 1.10 and

ć 2 p α p γ 1 p ( p α 1 ) S α p α p ( p α 1 ) .

Remark 1.13

In Theorem 1.12, in order to overcome the technical difficulties caused by the emergence of double Hardy-Littlewood-Sobolev critical terms, we introduce the new methods of adding mass term and the Hardy-Littlewood-Sobolev subcritical approximation to prove that m c 0 , p α is achieved.

From the analysis of Theorems 1.7, 1.10 and 1.12, we in addition obtain the following properties of a c and m c 0 , l .

Theorem 1.14

The following results hold:

  1. Suppose that the assumptions of Theorem 1.7 hold. Then the mapping c a c is a continuous and strictly decreasing mapping.

  2. Suppose that the assumptions of Theorems 1.10and 1.12hold. Then the mapping c m c 0 , l is continuous and strictly decreasing.

Secondly, we shall study the existence of normalized solutions to equation (1.1) in case of V ( x ) 0 . To be more precise, V ( x ) satisfies the following conditions:

  1. Let V C 2 ( R N , R ) and lim x V ( x ) = sup x R N V ( x ) = 0 . Moreover, there exist

    0 < σ 1 < 2 l N p ( N + α ) p 2 2 l N p ( N + α )

    and

    0 < σ 2 < min δ ¯ q + 1 δ ¯ q , 1 p q ( δ ¯ q + 2 ) 2 l N p ( N + α ) , q ( δ ¯ q + 1 ) ( 2 l N p ( N + α ) p q ( δ ¯ q + 1 ) ) q δ ¯ q ( 2 l N p ( N + α ) p q δ ¯ q )

    such that for all u E ,

    R N V ( x ) u p d x σ 1 u p p , R N V ( x ) u q d x σ 2 u q q .

  2. Let W ( x ) V ( x ) , x and lim x W ( x ) = 0 . Moreover, there exist

    σ 3 0 , min p , 2 l N p ( N + α ) p ( 1 σ 1 ) p , p ( 2 l N p ( N + α ) p 2 ) 2 l N p ( N + α ) ,

    0 < σ 4 < min q ( δ ¯ q + 1 δ ¯ q σ 2 ) , 2 l N p ( N + α ) p ( 1 σ 2 ) q ( δ ¯ q + 1 ) , q ( δ ¯ q + 1 ) ( 2 l N p ( N + α ) p q ( δ ¯ q + 1 ) ) + q δ ¯ q ( p q δ ¯ q 2 l N p ( N + α ) ) σ 2 2 l N p ( N + α ) 2 p q δ ¯ q

    such that for all u E ,

    R N W ( x ) u p d x σ 3 u p p , R N W ( x ) u q d x σ 4 u q q .

  3. Let Z ( x ) W ( x ) , x . Moreover, there exist

    0 < σ 5 < 2 l N p ( N + α ) p 2 2 l N p ( N + α ) p σ 3

    and

    0 < σ 6 < q ( δ ¯ q + 1 ) 2 l N p ( N + α ) p q ( δ ¯ q + 1 ) + q δ ¯ q q δ ¯ q 2 l N p ( N + α ) p σ 2 2 q δ ¯ q 2 l N p ( N + α ) p σ 4

    such that for all u E ,

    R N Z ( x ) u p d x σ 5 u p p , R N Z ( x ) u q d x σ 6 u q q .

  4. V ( x ) + W ( x ) 0 a.e. on R N .

Based on Theorems 1.10, 1.12, and 1.14, we treat equation (1.1) in case of V ( x ) 0 as the limit problem of equation (1.1) in case of V ( x ) 0 and give the following results.

Theorem 1.15

Assume that γ > 0 , p ¯ < l p α , and ( V 1 ) ( V 4 ) hold. Then there exist c * , c * * > 0 such that for every

0 < c < min { c ˇ , ć , c * , c * * }

and for μ > max { μ ˆ , μ ˜ } , equation (1.1) has a positive ground state u with some λ > 0 , where μ ˆ is introduced in Lemma 6.5, c ˇ , ć , and μ ˜ are introduced in Theorems 1.10and 1.12, respectively,

c * 1 q ( 1 σ 2 ) p 2 l N p ( N + α ) δ ¯ q + 1 + σ 4 q 2 l p δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 ( 2 l N p ( N + α ) ) μ K N , l , α 2 p α γ S α p α 1 2 l γ l q 1 p p α + 2 l ( 1 γ l ) 2 l γ l q ,

c * * 1 q 1 2 l γ l 2 p α γ S α p α ξ 2 l γ l 2 l γ l q ( μ K N , l , α γ l ) q 2 l γ l q 2 l γ l q p p α ( 2 l γ l q ) + 2 q l ( 1 γ l ) ,

and

ξ min 1 p ( 1 σ 1 ) , 1 q ( 1 σ 2 ) .

Remark 1.16

To our best knowledge, it seems to be the first work on the existence of normalized solutions for the double-phase problem with nonlocal critical reaction, potential, and mass supercritical perturbation. The appearance of different operators with different growth and potential term affect the geometry of this problem. Moreover, since E L ν ( R N ) ( p < ν < p * ) is not compact. We shall use the monotonicity of energy to limit equation and describe the relationship between the energy of equation (1.1), and its limit equation in detail to overcome the lack of compactness and prove that m c V , l is achieved.

This article is organized as follows. In Section 2, we study the existence of normalized solutions to (1.1) in case of V ( x ) 0 with L p -subcritical perturbation. In Section 3, we show the nonexistence of normalized solutions to (1.1) in case of V ( x ) 0 with L p -critical perturbation. Section 4 is devoted to proving the existence of normalized solutions to (1.1) in case of V ( x ) 0 with L p -supercritical perturbation. In Section 5, we give some properties of a c and m c 0 , l . In Section 6, based on Sections 4 and 5, we consider the existence of normalized solutions to (1.1) in case of V ( x ) 0 with L p -supercritical perturbation.

2 The low critical leading term with focusing L p -subcritical perturbation

In this section, we consider the existence of normalized solutions to (1.1) in case of p α < l < p ˜ and V ( x ) 0 . First, we give the following lemmas, which are necessary preparation.

Lemma 2.1

Assume that γ , μ > 0 , p α < l < p ˜ , and V ( x ) 0 . Then the following results hold:

  1. I 0 , l is bounded below and coercive on S c .

  2. Let q < 2 p α . Then c ¯ p c p a c < a c ¯ for 0 < c ¯ < c .

  3. a c < γ 2 p α S α 2 p α p c 2 p α .

Proof

( i ) Using (1.11) and (1.15), one has

I 0 , l ( u ) = 1 p u p p + 1 q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x 1 p u p p + 1 q u q q γ 2 p α S α p α c p p α μ 2 l C N , l , α u p 2 l δ l c 2 l ( 1 δ l ) ,

which yields that I 0 , l is bounded below and coercive on S c for 2 l δ l < p . So ( i ) holds.

( ii ) Let { u n } S c be a bounded minimizing sequence for a c . Then for any τ > 0 , it holds that τ u n S τ c and

I 0 , l ( τ u n ) τ q I 0 , l ( u n ) = τ p p u n p p + τ q q u n q q γ τ 2 p α 2 p α R N ( I α * u n p α ) u n p α d x μ τ 2 l 2 l R N ( I α * u n l ) u n l d x τ q p u n p p τ q q u n q q + γ τ q 2 p α R N ( I α * u n p α ) u n p α d x + μ τ q 2 l R N ( I α * u n l ) u n l d x = τ p τ q p u n p p + τ q τ 2 p α 2 p α γ R N ( I α * u n p α ) u n p α d x + τ q τ 2 l 2 l μ R N ( I α * u n l ) u n l d x .

Then combining the condition that q < 2 p α , we choose τ 0 > 1 such that

I 0 , l ( τ 0 u n ) < τ 0 q I 0 , l ( u n ) .

This means that a τ 0 c τ 0 q a c . Moreover, a τ 0 c = τ 0 q a c holds if and only if

(2.1) u n p p + R N ( I α * u n p α ) u n p α d x + R N ( I α * u n l ) u n l d x 0 as n .

In fact, for any u E , we define v c u u p and v s ( x ) s N p v ( s x ) for s > 0 . Then v s S c for all s > 0 . By direct calculation, we deduce that

I 0 , l ( v s ) = s p p v p p + s q ( δ ¯ q + 1 ) q v q q γ 2 p α R N ( I α * v p α ) v p α d x μ 2 l s 2 l N p ( N + α ) p R N ( I α * v l ) v l d x < 0

for s > 0 small enough. This implies that a c < 0 . By combining (2.1), we obtain that

0 > a c = lim n I 0 , l ( u n ) liminf n 1 q u n q q 0 .

This is impossible and a τ 0 c < τ 0 q a c < τ 0 p a c . Without loss of generality, we may assume that 0 < c ¯ < c . Then

c ¯ p c p a c < a c ¯ .

Hence, ( ii ) holds.

( iii ) By using (1.10) and (1.11), we choose v such that

v p p = S α , R N ( I α * v p α ) v p α d x = 1 .

Define u c v v p and u s ( x ) s N p u ( s x ) for s > 0 . Then u s S c for all s > 0 . By direct calculation, we derive that

I 0 , l ( u s ) = s p p u p p + s q ( δ ¯ q + 1 ) q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l s 2 l N p ( N + α ) p R N ( I α * u l ) u l d x = s p p u p p + s q ( δ ¯ q + 1 ) q u q q μ 2 l s 2 l N p ( N + α ) p R N ( I α * u l ) u l d x γ 2 p α S α 2 p α p c 2 p α < γ 2 p α S α 2 p α p c 2 p α

for s small enough. Therefore, ( iii ) holds.□

Lemma 2.2

Assume that γ , μ > 0 , p α < l < p ˜ , q < 2 p α , S α p α 2 p α p c ( p 2 ) p α , and V ( x ) 0 . Let { u n } E be a sequence such that I 0 , l ( u n ) a c and u n p c . Then the sequence { u n } is relatively compact in E .

Proof

By Lemma 2.1(i), we know that { u n } is bounded in E . We claim that there exists δ > 0 such that

(2.2) lim n + sup y R N B R ( y ) u n p d x δ for some R > 0 .

By assuming by contradiction and by Lemma I . 1 in [33], we deduce that u n 0 in L ν ( R N ) for p < ν < p * . It follows from (1.11) and Lemma 1.1 that

a c + o n ( 1 ) = I 0 , l ( u n ) = 1 p u n p p + 1 q u n q q γ 2 p α R N ( I α * u n p α ) u n p α d x + o n ( 1 ) 1 p u n p p + 1 q u n q q γ 2 p α S α p α c p p α + o n ( 1 ) γ 2 p α S α p α c p p α + o n ( 1 ) ,

which contradicts Lemma 2.1(iii) by the condition that S α p α 2 p α p c ( p 2 ) p α . Hence, (2.2) holds. Then, by (2.2), there exists { y n } R N such that u n ( x + y n ) u 0 in E . Set v n = u n ( x + y n ) u . If u 2 = c ˜ c , then c ˜ ( 0 , c ) . Denoting c ˆ n = v n p , and by using

u n ( x + y n ) p p = v n p p + u p p + o n ( 1 ) ,

we derive that c ˆ n ( 0 , c ) for n large enough and v n p c ˆ with c p = c ˜ p + c ˆ p . By [4], we easily obtain that

u n ( x + y n ) i i = v n i i + u i i + o n ( 1 ) ,

where i { p , q } . By combining the Brezis-Lieb lemma for nonlocal nonlinearities in [40] and Lemma 2.1(ii), we obtain

a c + o n ( 1 ) = I 0 , l ( u n ( x + y n ) ) = I 0 , l ( v n ) + I 0 , l ( u ) + o n ( 1 ) a c ¯ n + a c ˜ + o n ( 1 ) c ˆ n p c p a c + a c ˜ + o n ( 1 ) .

In view of Lemma 2.1(ii), letting n + , we find that

a c c ˆ p c p a c + a c ˜ > c ˆ p c p a c + c ˜ p c p a c = a c ,

which is a contradiction. Thus, u p = c and u n ( x + y n ) u in L p ( R N ) . By (1.15), we see that u n ( x + y n ) u in L ν ( R N ) for p ν < p * . As a consequence, we obtain that

a c = lim n + I 0 , l ( u n ) = lim n + I 0 , l ( u n ( x + y n ) ) I 0 , l ( u ) a c .

This means that I 0 , l ( u ) = a c and u n ( x + y n ) i u i for i { p , q } as n . That is, u S c is a minimizer of a c and u n ( x + y n ) u in E . So the proof of Lemma 2.2 is completed.□

Proof of Theorem 1.7

Based on Lemma 2.1(i), let { u n } S c be a sequence such that I 0 , l ( u n ) a c . Then, using Lemma 2.2, one obtains that there exists a sequence of points { y n } R N and a function u S c such that up to s subsequence u n ( + y n ) u in E . Hence, I 0 , l ( u ) = a c . Moreover, let u ˜ denote the Schwartz rerrangement of u . By using the Riesz rearrangement inequality in [31], for i { p , q } and ν ( p , p * ) ,

(2.3) u ˜ i u i u i , u ˜ ν = u ν , R N ( I α * u ˜ p α ) u ˜ p α d x R N ( I α * u p α ) u p α d x , R N ( I α * u ˜ l ) u ˜ l d x R N ( I α * u l ) u l d x ,

one has I 0 , l ( u ˜ ) = a c , namely, a c is attained by the real-valued positive and radially symmetric nonincreasing function u ˜ S c . In addition, since u ˜ is a critical point of I 0 , l restricted to S c , there exists a Lagrange multiplier λ c R such that I ( u ˜ ) + λ c u ˜ p 2 u ˜ = 0 . Then

λ c c p = u ˜ p p u ˜ q q + γ R N ( I α * u ˜ p α ) u ˜ p α d x + μ R N ( I α * u ˜ l ) u ˜ l d x = q I 0 , l ( u ˜ ) + q p 1 u ˜ p p + γ 1 q 2 p α R N ( I α * u ˜ p α ) u ˜ p α d x + μ 1 q 2 l R N ( I α * u ˜ l ) u ˜ l d x q a c ,

which implies that λ c > q γ 2 p α S α 2 p α p c 2 p α by Lemma 2.1(iii). Hence, the proof of Theorem 1.7 is completed.□

3 The low critical leading term with focusing L p -critical perturbation

In this section, we mainly show the nonexistence of normalized solutions to (1.1) in case of l = p ¯ and V ( x ) 0 under the suitable conditions. To be more precise, we give proof of Theorem 1.9.

Proof of Theorem 1.9

Assume that γ , μ > 0 , l = p ¯ and V ( x ) 0 . Let u be a solution to equation (1.1). By the Pohozeav identity, we know that u P c 0 , p ¯ . Then from (1.16), we deduce that

u p p + ( δ ¯ q + 1 ) u q q = 2 p ¯ N p ( N + α ) 2 p ¯ p μ R N ( I α * u p ¯ ) u p ¯ d x 2 p ¯ N p ( N + α ) 2 p ¯ p μ K N , p ¯ , α u q q c 2 p ¯ ( 1 γ p ¯ ) .

This means that P c 0 , p ¯ = if 2 p ¯ N p ( N + α ) 2 p ¯ p μ K N , p ¯ , α c 2 p ¯ ( 1 γ p ¯ ) < δ ¯ q + 1 . Hence, (1.1) does not admit a solution if 2 p ¯ N p ( N + α ) 2 p ¯ p μ K N , p ¯ , α c 2 p ¯ ( 1 γ p ¯ ) < δ ¯ q + 1 . In particular, if 2 p ¯ N p ( N + α ) 2 p ¯ p μ K N , p ¯ , α c 2 p ¯ ( 1 γ p ¯ ) = δ ¯ q + 1 , then u p p 0 . This is impossible. Then the proof of Theorem 1.9 is completed.□

Remark 3.1

From Theorem 1.9, if we let l = p ˜ and V ( x ) 0 , then letting u be a solution to equation (1.1) and using the Pohozaev identity and (1.15), we obtain that

u p p + ( δ ¯ q + 1 ) u q q = 2 p ˜ N p ( N + α ) 2 p ˜ p μ R N ( I α * u p ˜ ) u p ˜ d x 2 p ˜ N p ( N + α ) 2 p ˜ p μ C N , p ˜ , α u p p c 2 p ˜ ( 1 δ p ˜ ) .

This means that P c 0 , p ˜ = if 2 p ˜ N p ( N + α ) 2 p ˜ p μ C N , p ˜ , α c 2 p ˜ ( 1 δ p ˜ ) < 1 , then equation (1.1) does not admit a solution. In addition, if 2 p ˜ N p ( N + α ) 2 p ˜ p μ C N , p ˜ , α c 2 p ˜ ( 1 δ p ˜ ) = 1 , then we also have u q q 0 , which is a contradiction. To sum up, suppose that γ > 0 , l = p ˜ and V ( x ) 0 . If

0 < μ 2 p ˜ p [ 2 p ˜ N p ( N + α ) ] C N , p ˜ , α c 2 p ˜ ( 1 δ p ˜ ) ,

then equation (1.1) has no solution for any λ R .

4 The low critical leading term with focusing L p -supercritical perturbation

In this section, we consider the existence of normalized solutions to (1.1) in case of p ¯ < l p α and V ( x ) 0 . We shall restrict critical points of I 0 , l to a natural constraint manifold P c 0 , l , on which I 0 , l is bounded below.

Lemma 4.1

Assume that γ , μ > 0 , p ¯ < l p α , and V ( x ) 0 . For any u S c , there exists a unique t u > 0 such that u t u P c 0 , l = ( P c 0 , l ) and

I 0 , l ( u t u ) = sup t > 0 I 0 , l ( u t ) > 0 .

Proof

First, for any u P c 0 , l , we deduce that

( Ψ u l ) ( 1 ) = ( Ψ u l ) ( 1 ) 2 l N p ( N + α ) p 1 ( Ψ u l ) ( 1 ) = ( p 1 ) u p p + ( δ ¯ q + 1 ) [ q ( δ ¯ q + 1 ) 1 ] u q q μ 2 l 2 l N p ( N + α ) p 2 l N p ( N + α ) p 1 R N ( I α * u l ) u l d x 2 l N p ( N + α ) p 1 u p p ( δ ¯ q + 1 ) 2 l N p ( N + α ) p 1 u q q + μ 2 l 2 l N p ( N + α ) p 2 l N p ( N + α ) p 1 R N ( I α * u l ) u l d x = p 2 l N p ( N + α ) p u p p + ( δ ¯ q + 1 ) q ( δ ¯ q + 1 ) 2 l N p ( N + α ) p u q q < 0 .

Then P c 0 , l = ( P c 0 , l ) . Fix u S c and set

g ( t ) t p 2 l N p ( N + α ) p u p p + ( δ ¯ q + 1 ) t q ( δ ¯ q + 1 ) 2 l N p ( N + α ) p u q q for t > 0 .

Then u t P c 0 , l if and only if g ( t ) = μ 2 l 2 l N p ( N + α ) p R N ( I α * u l ) u l d x . Obviously, lim t 0 + g ( t ) = + , lim t + g ( t ) = 0 , and g ( t ) is decreasing on ( 0 , + ) . This means that there exists a unique t u > 0 such that u t u P c 0 , l . Moreover, we also know that ( Ψ u l ) ( t ) > 0 on ( 0 , t u ) and ( Ψ u l ) ( t ) < 0 on ( t u , + ) , which yields that

I 0 , l ( u t u ) = sup t > 0 I 0 , l ( u t ) > 0 .

So the proof of Lemma 4.1 is completed.□

Lemma 4.2

Assume that γ , μ > 0 , p ¯ < l p α , and V ( x ) 0 . Then there exists c ˇ > 0 such that the functional I 0 , l is bounded below by a positive constant and coercive on P c 0 , l for 0 < c < c ˇ .

Proof

For u P c 0 , l , we obtain that

(4.1) u p p + ( δ ¯ q + 1 ) u q q = 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x 2 l N p ( N + α ) 2 l p μ K N , l , α u q 2 l γ l c 2 l ( 1 γ l ) ,

which implies that

(4.2) u q q 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] c 2 l ( 1 γ l ) q 2 l γ l q .

By combining (1.11), (4.1), and (4.2), we deduce that

I 0 , l ( u ) = 1 p u p p + 1 q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x = 1 p p 2 l N p ( N + α ) u p p + 1 q ( δ ¯ q + 1 ) p 2 l N p ( N + α ) u q q γ 2 p α R N ( I α * u p α ) u p α d x 1 q ( δ ¯ q + 1 ) p 2 l N p ( N + α ) 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] c 2 l ( 1 γ l ) q 2 l γ l q γ 2 p α S α p α c p p α > 0 ,

provided that

0 < c < c ˇ

and

c ˇ 2 p α γ S α p α 2 l γ l q ( 2 l γ l q ) p p α + 2 q l ( 1 γ l ) 1 q ( δ ¯ q + 1 ) p 2 l N p ( N + α ) 2 l γ l q ( 2 l γ l q ) p p α + 2 q l ( 1 γ l ) 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] q p p α ( 2 l γ l q ) + 2 q l ( 1 γ l ) .

Hence, we complete the proof of Lemma 4.2.□

Lemma 4.3

Assume that γ , μ > 0 , p ¯ < l p α , and V ( x ) 0 . Then for 0 < c < c ˇ , we have

m c 0 , l inf u P c 0 , l I 0 , l ( u ) = inf u ( P c 0 , l ) r I 0 , l ( u ) > 0 ,

where ( P c 0 , l ) r P c 0 , l E r .

Proof

On the one hand, since ( P c 0 , l ) r P c 0 , l , we find that

inf u P c 0 , l I 0 , l ( u ) inf u ( P c 0 , l ) r I 0 , l ( u ) .

On the other hand, we need to show that

(4.3) inf u P c 0 , l I 0 , l ( u ) inf u ( P c 0 , l ) r I 0 , l ( u ) .

It follows from Lemma 4.1 that

(4.4) inf u ( P c 0 , l ) r I 0 , l ( u ) = inf u S c sup 0 < t t u I 0 , l ( u t ) .

Fix u S c and let u ˜ S c r be the Schwartz rearrangemnet of u , where S c r S c E r . Then from (2.3), for all t > 0 , we derive that

(4.5) I 0 , l ( u ˜ t ) = t p p u ˜ p p + t q ( δ ¯ q + 1 ) q u ˜ q q γ 2 p α R N ( I α * u ˜ p α ) u ˜ p α d x μ 2 l t 2 l N p ( N + α ) p R N ( I α * u ˜ l ) u ˜ l d x t p p u p p + t q ( δ ¯ q + 1 ) q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l t 2 l N p ( N + α ) p R N ( I α * u l ) u l d x .

Obviously, ( Ψ u ˜ l ) ( 0 ) = ( Ψ u l ) ( 0 ) = 0 and ( Ψ u ˜ l ) ( t ) ( Ψ u l ) ( t ) for t > 0 . This means that 0 < t u ˜ t u , which along with (4.5) yields that

sup 0 < t t u ˜ I 0 , l ( u ˜ t ) sup 0 < t t u I 0 , l ( u t ) .

Combining (4.4), we obtain that

inf u P c 0 , l I 0 , l ( u ) inf u ( P c 0 , l ) r I 0 , l ( u ) .

To sum up, in view of Lemma 4.2,

inf u P c 0 , l I 0 , l ( u ) = inf u ( P c 0 , l ) r I 0 , l ( u ) > 0 .

Hence, the proof of Lemma 4.3 is completed.□

Next, by applying the implicit function theorem on the C 1 function F : R × S c r R defined by F ( t , u ) = ( Ψ u l ) ( t ) , we know that the map u S c r t u R is of class C 1 . In addition, the map Φ : T u S c r T u t u S c r defined by ϕ ϕ t u is an isomorphism, where T u S c r denotes the tangent space to S c r in u . Moreover, similar to proof of Lemmas 3.15 and 3.16 in [17], we have the following lemma.

Lemma 4.4

Assume that γ , μ > 0 , p ¯ < l p α , and V ( x ) 0 . Then the following results hold:

  1. I ¯ ( u ) [ ϕ ] = I ( u t u ) [ ϕ t u ] for any u S c r and ϕ T u S c r , where the functional I ¯ : S c r R by I ¯ ( u ) = I 0 , l ( u t u ) .

  2. Suppose that is a homotopy-stable family of compact subsets of S c r with closed boundary Θ and set e inf H max u H I ¯ ( u ) . If Θ is contained in a connected component of ( P c 0 , l ) r and

    max { sup I ¯ ( Θ ) , 0 } < e < ,

    then there exists a Palais-Smale sequence { u n } ( P c 0 , l ) r for I 0 , l restricted to S c r at level e .

Based on Lemma 4.3, we obtain that

e ¯ = inf H ¯ max u H I ¯ ( u ) = inf u S c r I ¯ ( u ) = inf u ( P c 0 , l ) r I 0 , l ( u ) = inf u P c 0 , l I 0 , l ( u ) = m c 0 , l .

Then applying Lemma 4.4, we easily obtain the following lemma.

Lemma 4.5

Assume that γ , μ > 0 , p ¯ < l p α , and V ( x ) 0 . Then for 0 < c < c ˇ , there exists a Palais-Smale sequence { u n } ( P c 0 , l ) r for I 0 , l restricted to S c r at the level m c 0 , l > 0 .

Next, we will establish the existence of a Palais-Smale sequence { u n } ( P c 0 , l ) r for I 0 , l restricted to S c r at level m c 0 , l .

Lemma 4.6

Assume that γ , μ > 0 , p ¯ < l < p α , and V ( x ) 0 . Let { u n } ( P c 0 , l ) r be a bounded Palais-Smale sequence for I 0 , l restricted to S c r at level m c 0 , l > 0 . Then up to a subsequence, u n u strongly in E r for 0 < c < c ˇ .

Proof

Since { u n } ( P c 0 , l ) r is a bounded Palais-Smale sequence of I 0 , l restricted to S c r , there exists u E r such that u n u weakly in E r , u n u strongly in L ν ( R N ) for p < ν < p * and u n ( x ) u ( x ) a.e. on R N . By the Lagrange multipliers rule, there exists λ n R such that for every ψ E r ,

R N u n p 2 u n ψ d x + R N u n q 2 u n ψ d x + λ n R N u n p 2 u n ψ d x γ R N ( I α * u n p α ) u n p α 2 u n ψ d x μ R N ( I α * u n l ) u n l 2 u n ψ d x = o n ( 1 ) ψ E .

Take ψ = u n . We see that { λ n } is bounded by (1.11) and (1.14). Then we assume that λ n λ R . By combining P 0 , l ( u n ) = o n ( 1 ) , one has

(4.6) λ c p = lim n λ n c p = lim n γ R N ( I α * u n p α ) u n p α d x + 1 2 l N p ( N + α ) 2 l p μ R N ( I α * u n l ) u n l d x + δ ¯ q u n q q ,

which implies that λ 0 . Now we claim that λ 0 . Otherwise, it follows from (4.6) that u n q q = o n ( 1 ) ,

R N ( I α * u n p α ) u n p α d x = o n ( 1 )

and

R N ( I α * u n l ) u n l d x = o n ( 1 ) ,

which along with P 0 , l ( u n ) = o n ( 1 ) yields that u n p p = o n ( 1 ) . This implies that I 0 , l ( u n ) = o n ( 1 ) , which contradicts with m c 0 , l > 0 . Thus λ > 0 .

Next, we show that u 0 . Otherwise, using the Sobolev embedding theorem, we obtain

R N ( I α * u n l ) u n l d x = o n ( 1 ) ,

which together with P 0 , l ( u n ) = o n ( 1 ) implies that u n p p = o n ( 1 ) and u n q q = o n ( 1 ) . Hence, it follows from (4.6) that

lim n γ R N ( I α * u n p α ) u n p α d x = lim n + λ n c p = λ c p > 0 .

Then

m c 0 , l = lim n I 0 , l ( u n ) = γ 2 p α lim n R N ( I α * u n p α ) u n p α d x 0 ,

which contradicts with Lemma 4.3. So u 0 .

In the last, we claim that u n u strongly in E . Indeed, by weak convergence, we obtain

Δ p u Δ q u + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u l ) u l 2 u , in R N

and P 0 , l ( u ) = 0 . Denote v n u n u . Similar to the proof of Lemma 2.2, by Brezis-Lieb Lemma in [12], we have

u n i i = u i i + v n i i + o n ( 1 ) , for i { p , q } ,

R N ( I α * u n j ) u n j d x = R N ( I α * u j ) u j d x + R N ( I α * v n j ) v n j d x + o n ( 1 ) , for j { p α , l } .

Moreover,

R N ( I α * u n l ) u n l d x = R N ( I α * u l ) u l d x + o n ( 1 ) .

Hence, in view of P 0 , l ( u n ) = o n ( 1 ) , we see that

u n p p + ( δ ¯ q + 1 ) u n q q = 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x + o n ( 1 ) .

In addition, we observe that

P 0 , l ( u ) = u p p + ( δ ¯ q + 1 ) u q q 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x = 0 .

Then v n p p = o n ( 1 ) and v n q q = o n ( 1 ) . Combining the fact that

v n p p + v n q q + λ n v n p p = γ R N ( I α * v n p α ) v n p α d x + μ R N ( I α * v n l ) v n l d x ,

we denote that

b lim n + λ n v n p p = lim n + γ R N ( I α * v n p α ) v n p α d x .

Repeating the same argument as proving u 0 , we obtain that b = 0 . Therefore, u n u strongly in E . So the proof of Lemma 4.6 is completed.□

Proof of Theorem 1.10

In view of Lemmas 4.2 and 4.5, there exists a bounded Palais-Smale sequence { u n } ( P c 0 , l ) r for I 0 , l restricted to S c r at the level m c 0 , l . Applying Lemma 4.6, up to a subsequence, u n u strongly in E r for 0 < c < c ˇ , which along with Lemma 4.3 yields that u is a radially symmetric ground state solution of (1.1) for some λ > 0 . Let u ˜ be the Schwartz symmetrization rearrangement of u . Similar to the proof of Theorem 1.7, we have P 0 , l ( u ˜ ) 0 , and there eixsts a unique t ( 0 , 1 ] such that P 0 , l ( u ˜ t ) = 0 . So u ˜ t P c 0 , l and

I 0 , l ( u ˜ ) = 1 p u ˜ p p + 1 q u ˜ q q γ 2 p α R N ( I α * u ˜ p α ) u ˜ p α d x μ 2 l R N ( I α * u ˜ l ) u ˜ l d x 1 p u p p + 1 q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x = I 0 , l ( u ) = m c 0 , l .

Then we know that m c 0 , l is attained by the real-valued positive and radially symmetric nonincreasing function. Moreover, it follows from (4.2) that

λ c p = γ R N ( I α * u p α ) u p α d x + μ R N ( I α * u l ) u l d x u p p u q q = γ R N ( I α * u p α ) u p α d x + 1 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x + δ ¯ q u q q > δ ¯ q 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] c 2 l ( 1 γ l ) q 2 l γ l q .

This means that

λ > δ ¯ q 2 l p ( δ ¯ q + 1 ) K N , l , α μ [ 2 l N p ( N + α ) ] q 2 l γ l q c 2 l ( 1 γ l ) q + p ( 2 l γ l q ) 2 l γ l q .

Thus the proof of Theorem 1.10 is completed.□

Next we study the existence of normalized solutions to (1.1) in case of l = p α and V ( x ) 0 . Before this, we first give some properties of m c 0 , p α .

Lemma 4.7

Assume that γ , μ > 0 , l = p α , and V ( x ) 0 . Then

m c 0 , p α limsup l p α m c 0 , l > 0

for 0 < c < c ˇ .

Proof

By the definition of m c 0 , p α , for any fixed ε ( 0 , 1 ) , there exists u P c 0 , p α such that I 0 , p α ( u ) < m c 0 , p α + ε . Using the definition of Ψ u p α ( t ) , we find that there exists t 0 > 0 large enough such that I 0 , p α ( u t 0 ) 2 . It follows from the Young inequality that

u l p α l p α p α u p α + l p α p α p α u p α .

Then, the Lebesgue dominated convergence theorem implies that

μ 2 l t 2 l N p ( N + α ) p R N ( I α * u l ) u l d x

is continuous on l [ p ¯ , p α ] uniformly with t [ 0 , t 0 ] . Therefore, there exists δ ¯ > 0 such that

I 0 , l ( u t ) I 0 , p α ( u t ) < ε

for p α δ ¯ l p α and 0 < t < t 0 , which yields that I 0 , l ( u t 0 ) 1 for all p α δ ¯ l p α . Since I 0 , l ( u t ) > 0 for t > 0 small enough for every l [ p α , p α ] , it follows from Lemma 4.1 that the unique critical maximum point t l of I 0 , l ( u t ) belongs to P 0 , l ( u t l ) = 0 . Since u P c 0 , p α , we derive that I 0 , p α ( u ) = max t > 0 I 0 , p α ( u t ) . As a consequence,

m c 0 , l I 0 , l ( u t l ) I 0 , p α ( u t l ) + ε I 0 , p α ( u ) + ε < m c 0 , p α + 2 ε

for any p α δ ¯ l p α . Hence, limsup l p α m c 0 , l m c 0 , p α . Moreover, applying Lemma 4.2, we find that when 0 < c < c ˇ , m c 0 , p α limsup l p α m c 0 , l > 0 . Thus, the proof of Lemma 4.7 is completed.□

To clearly determine the weak convergence of nonlocal terms, we first give some necessary lemmas as follows.

Lemma 4.8

[54] Let Ω R N be a domain, q ( 1 , ) and { u n } be a bounded sequence in L q ( Ω ) . If u n u a.e. on Ω , then u n u weakly in L q ( Ω ) .

Lemma 4.9

[10] If u L ν ( R N ) , 1 ν < + is a radial nonincreasing function, then one has

u ( x ) x N ν N S N 1 1 ν u ν , x 0 ,

where S N 1 is the area of the unit sphere in R N .

Lemma 4.10

Assume that l = p α , V ( x ) 0 , 0 < c < min { c ˇ , ć } , and

γ α p + α 2 p α p p S α 2 p α p ( S α ) p α ( 2 p α p ) p ( p α 1 ) μ 2 p α p p ( p α 1 ) .

Then there exists μ ˜ > 0 large enough such that for every μ > μ ˜ , the infimum m c 0 , p α > 0 is achieved by u . Moreover, there exists λ > 0 such that ( u , λ ) is a solution to (1.1). Here, c ˇ is defined in Lemma 4.2and ć 2 p α p γ 1 p ( p α 1 ) S α p α p ( p α 1 ) .

Proof

Let l n ( p α ) as n . In view of Theorem 1.10 and Lemma 4.7, there exists a sequence of positive and radially nonincreasing functions { u n u l n } P c 0 , l n such that

I 0 , l n ( u n ) = m c 0 , l n m c 0 , p α + 1 ,

which implies that { u n } is bounded in E r . Then there exists u E r such that u n u in E r , u n u in L ν ( R N ) for p < ν < p * and u n ( x ) u ( x ) a.e. on R N . Furthermore, by the Lagrange multipliers rule, there exists λ n R such that for every ψ E ,

(4.7) R N u n p 2 u n ψ d x + R N u n q 2 u n ψ d x + λ n R N u n p 2 u n ψ d x = γ R N ( I α * u n p α ) u n p α 2 u n ψ d x + μ R N ( I α * u n l n ) u n l n 2 u n ψ d x + o n ( 1 ) ψ E .

Take ψ = u n . Then

λ n c p = u n p p u n q q + γ R N ( I α * u n p α ) u n p α d x + μ R N ( I α * u n l n ) u n l n d x + o n ( 1 ) .

Combining Lemma 1.1 and the Sobolev embedding theorem, we see that { λ n } is bounded. Thus, there exists λ R such that λ n λ as n . In view of P 0 , l n ( u n ) = o n ( 1 ) , one has

λ c p = lim n λ n c p = lim n γ R N ( I α * u n p α ) u n p α d x + 1 2 l n N p ( N + α ) 2 l n p μ R N ( I α * u n l n ) u n l n d x + δ ¯ q u n q q 0 .

This means that λ 0 . Now we claim that λ 0 . Otherwise, we obtain that

R N ( I α * u n p α ) u n p α d x = o n ( 1 ) , R N ( I α * u n l n ) u n l n d x = o n ( 1 ) , u n q q = o n ( 1 ) .

Moreover, we have I 0 , l n ( u n ) = o n ( 1 ) . This is impossible by the fact that liminf n m c 0 , l n > 0 . So λ > 0 .

Since l n ( p α ) as n , by the Hölder inequality, we derive that { u n l n } is bounded in L 2 N N + α ( R N ) , { u n l n 2 u n } is bounded in L 2 N p α ( p α 1 ) ( N + α ) ( R N ) , { u n l n 2 u n ψ } is bounded in L 2 N N + α ( R N ) and u p α 2 u ψ L 2 N N + α ( R N ) for any ψ C 0 ( R N ) . By Lemmas 1.1 and 4.8, one has u n l n u p α weakly in L 2 N N + α ( R N ) and I α * ( u p α 2 u ψ ) L 2 N N α ( R N ) . Therefore,

R N ( I α * u n l n ) u p α 2 u ψ d x R N ( I α * u p α ) u p α 2 u ψ d x

as n . It follows from N > p and p α > 1 that N N p p ( p α 1 ) and N N p p ( p α 1 ) 2 N N + α , + . Since l n p α and ψ L r ( R N ) for r ( 1 , ) , by the Young inequality, the Hölder inequality and Lemma 4.9 with ν = N p N p , there exists a constant C > 0 independent of n such that

u n l n 2 u n ψ C ( u n p α 1 ψ + u n p α 1 ψ ) C x p N p ( p α 1 ) ψ + x p N p ( p α 1 ) ψ L 2 N N + α ( R N ) .

By Lemma 1.1 and the Lebesgue-dominated convergence theorem,

R N ( I α * u n l n ) u n l n 2 u n ψ d x R N ( I α * u n l n ) u p α 2 u ψ d x = o n ( 1 ) .

By combining this with (4.7), we deduce that

o n ( 1 ) = R N u n p 2 u n ψ d x + R N u n q 2 u n ψ d x + λ n R N u n p 2 u n ψ d x γ R N ( I α * u n p α ) u n p α 2 u n ψ d x μ R N ( I α * u n l n ) u n l n 2 u n ψ d x R N u p 2 u ψ d x + R N u q 2 u ψ d x + λ R N u p 2 u ψ d x γ R N ( I α * u p α ) u p α 2 u ψ d x μ R N ( I α * u p α ) u p α 2 u ψ d x

as n . This means that u is a weak solution of

Δ p u Δ q u + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u p α ) u p α 2 u , in R N

and P 0 , p α ( u ) = 0 . Now we show that u 0 . Otherwise, by using P 0 , l n ( u n ) = 0 , (1.12) and the Young inequality,

u n l n p α l n p α ν u n ν + l n ν p α ν u n p α for l n < ν < p α ,

one has

(4.8) u n p p + ( δ ¯ q + 1 ) u n q q = 2 l n N p ( N + α ) 2 l n p μ R N ( I α * u n l n ) u n l n d x 2 l n N p ( N + α ) 2 l n p l n ν p α ν 2 μ R N ( I α * u n p α ) u n p α d x + o n ( 1 ) 2 l n N p ( N + α ) 2 l n p l n ν p α ν 2 μ u n p p S α p α + o n ( 1 ) μ u n p p S α p α + o n ( 1 ) .

Based on the fact that liminf n u n p p > 0 , it follows from (4.8) that

(4.9) limsup n u n p p ( S α ) p α p α 1 μ 1 p α 1 .

By using Lemma 4.7, (4.9), and the fact that P 0 , l n ( u n ) = o n ( 1 ) , we deduce that

(4.10) m c 0 , p α limsup n m c 0 , l n = limsup n 1 p u n p p + 1 q u n q q γ 2 p α R N ( I α * u n p α ) u n p α d x μ 2 l n R N ( I α * u n l n ) u n l n d x = limsup n 1 p p 2 l n N p ( N + α ) u n p p + 1 q p ( δ ¯ q + 1 ) 2 l n N p ( N + α ) u n q q γ 2 p α R N ( I α * u n p α ) u n p α d x 1 p p 2 p α N p ( N + α ) ( S α ) p α p α 1 μ 1 p α 1 γ 2 p α S α p α c p p α .

In addition, by using (1.10), we let v ε c V ε V ε p , where S α is achieved by V ε C ˆ ε ε 2 + x y 2 N p . We note that V ε p p is a positive constant independent ε ,

V ε p p = O ( ε p ) , V ε q q = O ε q N p q + N , R N ( I α * V ε p α ) V ε p α d x = O ε 2 p α γ p α N p + 1 N q .

Obviously, v ε p = c . From Lemma 4.1, there exists a unique constant t ε > 0 independent of ε such that ( v ε ) t ε P c 0 , p α and

I 0 , p α ( ( v ε ) t ε ) = sup t 0 I 0 , p α ( ( v ε ) t ) ,

which yields that

(4.11) m c 0 , p α sup t 0 I 0 , p α ( ( v ε ) t ) .

By direct calculation, it follows from (4.11) that there exists μ ˜ > 0 large enough such that when μ > μ ˜ ,

m c 0 , p α + 1 p c p I 0 , p α ( ( v ε ) t ε ) + 1 p c p = I 0 , p α ( ( v ε ) t ε ) + 1 p v ε p p = ( t ε ) p p v ε p p + ( t ε ) q ( δ ¯ q + 1 ) q v ε q q + 1 p v ε p p γ 2 p α R N ( I α * v ε p α ) v ε p α d x μ 2 p α ( t ε ) 2 p α N p ( N + α ) p R N ( I α * v ε p α ) v ε p α d x = c p ( t ε ) p p V ε p p V ε p p + c q ( t ε ) q ( δ ¯ q + 1 ) q V ε p q V ε q q γ c 2 p α 2 p α V ε p 2 p α R N ( I α * V ε p α ) V ε p α d x + c p p V ε p p V ε p p μ 2 p α ( t ε ) 2 p α N p ( N + α ) p c 2 p α V ε p 2 p α R N ( I α * V ε p α ) V ε p α d x = c p ( t ε ) p p V ε p p O ( ε p ) + c q ( t + ε ) q ( δ ¯ q + 1 ) q V ε p q O ε q N p q + N + c p p V ε p p V ε p p μ 2 p α ( t ε ) 2 p α N p ( N + α ) p c 2 p α V ε p 2 p α O ε 2 p α γ p α N p + 1 N q γ c 2 p α 2 p α V ε p 2 p α R N ( I α * V ε p α ) V ε p α d x < 1 p 1 2 p α γ p 2 p α p S α 2 p α 2 p α p .

This means that

(4.12) m c 0 , p α < 1 p 1 2 p α γ p 2 p α p S α 2 p α 2 p α p 1 p c p .

Then combining (4.10), we derive that

1 p p 2 p α N p ( N + α ) ( S α ) p α p α 1 μ 1 p α 1 γ 2 p α S α p α c p p α < 1 p 1 2 p α γ p 2 p α p S α 2 p α 2 p α p 1 p c p .

However, since

γ α p + α 2 p α p p S α 2 p α p ( S α ) p α ( 2 p α p ) p ( p α 1 ) μ 2 p α p p ( p α 1 ) and c 2 p α p γ 1 p ( p α 1 ) S α p α p ( p α 1 ) ,

one has

1 p p 2 p α N p ( N + α ) ( S α ) p α p α 1 μ 1 p α 1 γ 2 p α S α p α c p p α 1 p 1 2 p α γ p 2 p α p S α 2 p α 2 p α p 1 p c p .

This is a contradiction. So u 0 .

Next we show that m c 0 , p α is attained. Denote u p c 1 c , θ c 1 c 1 . Setting ω = θ N p p u ( θ x ) , we have ω p p = c p , which shows that ω S c . It follows from Lemma 4.1 that there exists a unique t ω > 0 such that ω t ω P c 0 , p α . Moreover, by simple calculation, one obtains

ω p p = u p p , ω q q = θ q ( N p ) p + q N u q q < u q q ,

R N ( I α * ω p α ) ω p α d x = R N ( I α * u p α ) u p α d x

and

R N ( I α * ω p α ) ω p α d x = θ 2 N p p p α N α R N ( I α * u p α ) u p α d x > R N ( I α * u p α ) u p α d x .

By combining the fact that P 0 , p α ( u ) = 0 , we easily know that t ω 1 . In addition, u satisfies the following equality

(4.13) N p p u p p + N q q u q q + λ N p u p p = N + α 2 p α γ R N ( I α * u p α ) u p α d x + N + α 2 p α μ R N ( I α * u p α ) u p α d x .

Then we deduce that

(4.14) m c 0 , p α I 0 , p α ( ω t ω ) = I 0 , p α t ω N p ω ( t ω x ) = t ω p p ω p p + t ω q ( δ ¯ q + 1 ) q ω q q γ 2 p α R N ( I α * ω p α ) ω p α d x μ 2 p α t ω 2 p α N p ( N + α ) p R N ( I α * ω p α ) ω p α d x = 1 p p 2 p α N p ( N + α ) t ω p ω p p + 1 q p ( δ ¯ q + 1 ) 2 p α N p ( N + α ) t ω q ( δ ¯ q + 1 ) ω q q γ 2 p α R N ( I α * ω p α ) ω p α d x 1 p p 2 p α N p ( N + α ) ω p p + 1 q p ( δ ¯ q + 1 ) 2 p α N p ( N + α ) ω q q γ 2 p α R N ( I α * ω p α ) ω p α d x = 1 p p 2 p α N p ( N + α ) u p p + 1 q p ( δ ¯ q + 1 ) 2 p α N p ( N + α ) θ q ( N p ) p + q N u q q θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x < 1 p p 2 p α N p ( N + α ) u p p + 1 q p ( δ ¯ q + 1 ) 2 p α N p ( N + α ) u q q R N ( I α * u p α ) u p α d x + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x = 1 p u p p + 1 q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 p α R N ( I α * u p α ) u p α d x + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x = 1 q N q q ( N p ) u q q + N + α N p 1 γ 2 p α R N ( I α * u p α ) u p α d x + N + α N p 1 μ 2 p α R N ( I α * u p α ) u p α d x λ N p ( N p ) u p p + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x .

On the other hand, similar to (4.13), we also have

N p p u n p p + N q q u n q q + λ n N p u n p p = N + α 2 p α γ R N ( I α * u n p α ) u n p α d x + N + α 2 l n μ R N ( I α * u n l n ) u n l n d x .

Then

I 0 , l n ( u n ) + λ n N p ( N p ) u n p p = 1 q N q q ( N p ) u n q q + N + α N p 1 γ 2 p α R N ( I α * u n p α ) u n p α d x + N + α N p 1 μ 2 l n R N ( I α * u n l n ) u n l n d x .

Therefore, in view of (4.14), one infers that

m c 0 , p α 1 q N q q ( N p ) u q q + N + α N p 1 γ 2 p α R N ( I α * u p α ) u p α d x + N + α N p 1 μ 2 p α R N ( I α * u p α ) u p α d x λ N p ( N p ) u p p + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x liminf n 1 q N q q ( N p ) u n q q + N + α N p 1 γ 2 p α R N ( I α * u n p α ) u n p α d x + N + α N p 1 μ 2 p α R N ( I α * u n p α ) u n p α d x λ N p ( N p ) c 1 p + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x liminf n m c 0 , l n + λ N p ( N p ) ( c p c 1 p ) + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x limsup n m c 0 , l n m c 0 , p α

provided that

λ N p ( N p ) ( c p c 1 p ) + 1 θ 2 N p p p α N α γ 2 p α R N ( I α * u p α ) u p α d x 0 .

To sum up, if c = c 1 , then m c 0 , p α is attained by w = ω for all γ > 0 . If c 1 < c , then m c 0 , p α is achieved by w = ω t ω when

(4.15) γ 2 p α λ N ( c p c 1 p ) p ( N p ) θ 2 N p p p α N α 1 R N ( I α * u p α ) u p α d x .

Here, using the condition

γ α p + α 2 p α p p S α 2 p α p ( S α ) p α ( 2 p α p ) p ( p α 1 ) μ 2 p α p p ( p α 1 ) ,

we find that for μ large enough, (4.15) holds. Hence, there exists μ ˜ > 0 such that when μ > μ ˜ , (4.15) holds. In the last, since the infimum m c 0 , p α is achieved by w , there exist λ and ξ such that

(4.16) Δ p w Δ q w + λ w p 2 w γ ( I α * w p α ) w p α 2 w μ ( I α * w p α ) w p α 2 w = ξ [ p Δ p w q ( δ ¯ q + 1 ) Δ q w 2 p α μ ( I α * w p α ) w p α 2 w ] .

That is,

( 1 ξ p ) Δ p w ( 1 ξ q ( δ ¯ q + 1 ) ) Δ q w + λ w p 2 w = γ ( I α * w p α ) w p α 2 w + ( 1 2 ξ p α ) μ ( I α * w p α ) w p α 2 w .

Similarly, w satisfies the following Pohozaev identity:

( 1 ξ p ) w p p + ( 1 ξ q ( δ ¯ q + 1 ) ) ( δ ¯ q + 1 ) w q q = ( 1 2 ξ p α ) μ R N ( I α * w p α ) w p α d x .

By combining P 0 , p α ( w ) = 0 , we derive that

( q ( δ ¯ q + 1 ) p ) ξ w p p = ( q ( δ ¯ q + 1 ) 2 p α ) ξ μ R N ( I α * w p α ) w p α d x ,

whcih implies that ξ = 0 . Moreover, by (4.16) and P 0 , p α ( w ) = 0 , one obtains

λ = 1 c p R N ( I α * w p α ) w p α d x + δ ¯ q w q q > 0 .

Hence, the proof of Lemma 4.10 is completed.□

Proof of Theorem 1.12

In view of Lemma 4.10, we know that w is a ground state solution to (1.1) for some λ > 0 . The proof of Theorem 1.12 is completed.□

5 Qualitative properties of the mappings a c and m c 0 , l

In this section, we discuss the continuity and monotonicity of a c and m c 0 , l . Next we give the details of proof in the following argument.

Proof of Theorem 1.14

(i) Let c n c as n . From the definition of a c that for any ε > 0 , there exists u n S c n such that

I 0 , l ( u n ) a c + ε .

Suppose that v n c c n u n and v n S c . Note that c c n 1 as n . Then

a c I 0 , l ( v n ) = I 0 , l ( u n ) + o n ( 1 ) .

In summary, we obtain that a c a c n + ε + o n ( 1 ) . Similarly, we also obtain that a c n a c + ε + o n ( 1 ) . Hence, by the arbitrariness of ε > 0 , we derive that a c n a c as n . Moreover, based on the proof of Lemma 2.1(ii), one has a τ 0 c τ 0 p a c . Without loss of generality, we may assume that 0 < c ˘ < c c ˘ . Then

a c < c c c ˘ a c c ˘ = a c c ˘ + c ˘ c c ˘ a c c ˘ < a c c ˘ + a c ˘ .

This means that a c < a c ˘ + a c c ˘ for 0 < c ˘ < c . By combining this with the continuity of a c , we obtain that a c is strict decreasing.

( ii ) Similar to the proof of ( i ) , we easily know that m c 0 , l is continuous with respect to c . Now we show that c m c 0 , l is strictly decreasing. Based on Theorems 1.10 and 1.12, let 0 < c ¯ 1 < c ¯ 2 < + , θ ¯ = c ¯ 1 c ¯ 2 < 1 . Assume that m c ¯ 1 0 , l is achieved by u . By setting ω θ ¯ N p p u ( θ ¯ x ) , one obtains ω p p = c ¯ 2 p , which shows that ω S c ¯ 2 . It follows from Lemma 4.1 that there exists t ω > 0 such that ω t ω P c 0 , l . Then by simple calculation, one obtains

ω p p = u p p , ω q q = θ ¯ q ( N p ) p + q N u q q < u q q ,

R N ( I α * ω p α ) ω p α d x = θ ¯ 2 N p p p α N α R N ( I α * u p α ) u p α d x > R N ( I α * u p α ) u p α d x

and

R N ( I α * ω l ) ω l d x = θ ¯ 2 N p p l N α R N ( I α * u l ) u l d x > R N ( I α * u l ) u l d x .

Thus,

m c ¯ 2 0 , l I 0 , l ( ω t ω ) = I 0 , l t ω N p ω ( t ω x ) = t ω p p ω p p + t ω q ( δ ¯ q + 1 ) q ω q q γ 2 p α R N ( I α * ω p α ) ω p α d x μ 2 l t ω 2 l N p ( N + α ) p R N ( I α * ω l ) ω l d x = t ω p p u p p + t ω q ( δ ¯ q + 1 ) q θ ¯ q ( N p ) p + q N u q q γ 2 p α θ ¯ 2 N p p p α N α R N ( I α * u p α ) u p α d x μ 2 l t ω 2 l N p ( N + α ) p θ ¯ 2 N α p l N α R N ( I α * u l ) u l d x < t ω p p u p p + t ω q ( δ ¯ q + 1 ) q u q q γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l t ω 2 l N p ( N + α ) p R N ( I α * u l ) u l d x = I 0 , l ( u t ω ) max t > 0 I 0 , l ( u t ) = m c ¯ 1 0 , l .

This means that m c ¯ 2 0 , l < m c ¯ 1 0 , l , which implies that c m c 0 , l is strictly decreasing. So we complete the proof of Theorem 1.14.□

6 The nonautonomous problem

In this section, we consider the existence of normalized solutions to equation (1.1) in case of p ¯ < l p α and V ( x ) 0 . From the condition ( V 1 ) , we know that equation (1.1) in case of V ( x ) 0 can be the limit problem to equation (1.1) in case of V ( x ) 0 . Then the existence of normalized solutions and properties of energy m c 0 , l to equation (1.1) in the autonomous case play the crucial role in this section, which will be explained later in the proof.

The following lemma helps us to show that I V , l is bounded away from 0 on P c V , l .

Lemma 6.1

Assume that γ , μ > 0 , p ¯ < l p α , and ( V 1 ) , ( V 2 ) , hold. For any u P c V , l ,

(6.1) u q 2 l p δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 ( 2 l N p ( N + α ) ) μ K N , l , α c 2 l ( 1 γ l ) 1 2 l γ l q > 0 .

Proof

For any u P c V , l , in view of ( V 1 ) , ( V 2 ) , and (1.16), one has

u p p + ( δ ¯ q + 1 δ ¯ q σ 2 ) u q q = u p p + ( δ ¯ q + 1 ) u q q + δ ¯ q R N V ( x ) u q d x = 1 p R N W ( x ) u p d x + 1 q R N W ( x ) u q d x + 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x 1 p σ 3 u p p + 1 q σ 4 u q q + 2 l N p ( N + α ) 2 l p μ K N , l , α u q 2 l γ l c 2 l ( 1 γ l ) ,

which implies that

1 σ 3 p u p p + δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 u q q 2 l N p ( N + α ) 2 l p μ K N , l , α u q 2 l γ l c 2 l ( 1 γ l ) .

Since q < 2 l γ l , we know that (6.1) holds. Hence, we complete the proof of Lemma 6.1.□

Lemma 6.2

Assume that γ , μ > 0 , p ¯ < l p α , and ( V 1 ) , ( V 2 ) hold. If c satisfies

0 < c < c * ,

where

c * 1 q ( 1 σ 2 ) p 2 l N p ( N + α ) δ ¯ q + 1 + σ 4 q 2 l p δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 ( 2 l N p ( N + α ) ) μ K N , l , α 2 p α γ S α p α 1 2 l γ l q 1 p p α + 2 l ( 1 γ l ) 2 l γ l q ,

then m c V , l > 0 .

Proof

For any u P c V , l , by using ( V 1 ) , ( V 2 ) , we infer that

1 + σ 3 p u p p + δ ¯ q + 1 + 1 q σ 4 u q q u p p + ( δ ¯ q + 1 ) u q q + δ ¯ q R N V ( x ) u q d x 1 p R N W ( x ) u p d x 1 q R N W ( x ) u q d x = 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x ,

which along with (1.11), (6.1), and the condition 0 < c < c * yields that

I V , l ( u ) = 1 p u p p + 1 q u q q + 1 p R N V ( x ) u p d x + 1 q R N V ( x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x 1 p ( 1 σ 1 ) u p p + 1 q ( 1 σ 2 ) u q q γ 2 p α S α p α c p p α p 2 l N p ( N + α ) 1 + σ 3 p u p p + δ ¯ q + 1 + 1 q σ 4 u q q 1 p ( 1 σ 1 ) p 2 l N p ( N + α ) 1 + σ 3 p u p p + 1 q ( 1 σ 2 ) p 2 l N p ( N + α ) δ ¯ q + 1 + σ 4 q u q q γ 2 p α S α p α c p p α > 1 q ( 1 σ 2 ) p 2 l N p ( N + α ) δ ¯ q + 1 + σ 4 q 2 l p δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 ( 2 l N p ( N + α ) ) μ K N , l , α c 2 l ( 1 γ l ) 1 2 l γ l q γ 2 p α S α p α c p p α > 0 .

Then we see that m c V , l > 0 . So we complete the proof of Lemma 6.2.□

Next, similar to the aforementioned sections, we consider the decomposition of P c V , l into the disjoint union

P c V , l = ( P ¯ c V , l ) + ( P ¯ c V , l ) 0 ( P ¯ c V , l ) ,

where

( P ¯ c V , l ) + = { u S c : ( Ψ ¯ u ) ( 0 ) = 0 , ( Ψ ¯ u ) ( 0 ) > 0 } , ( P ¯ c V , l ) 0 = { u S c : ( Ψ ¯ u ) ( 0 ) = 0 , ( Ψ ¯ u ) ( 0 ) = 0 } , ( P ¯ c V , l ) = { u S c : ( Ψ ¯ u ) ( 0 ) = 0 , ( Ψ ¯ u ) ( 0 ) < 0 } ,

and for any u S c , let ( s * u ) ( x ) e N s p u ( e s x ) , one has s * u S c and

Ψ ¯ u ( s ) I V , l ( s * u ) = e p s p u p p + e q ( δ ¯ q + 1 ) s q u q q + 1 p R N V ( e s x ) u p d x + e q δ ¯ q s q R N V ( e s x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x .

Now we give some properties of P c V , l .

Lemma 6.3

Assume that ( V 1 ) , ( V 2 ) , and ( V 3 ) hold. Then P c V , l = ( P ¯ c V , l ) .

Proof

For any u P c V , l , P V , l ( u ) = 0 , namely,

(6.2) u p p + ( δ ¯ q + 1 ) u q q + δ ¯ q R N V ( x ) u q d x = 1 p R N W ( x ) u p d x + 1 q R N W ( x ) u q d x + 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x .

In addition, by direct calculation, one has

(6.3) Ψ ¯ u ( 0 ) = p u p p + q ( δ ¯ q + 1 ) 2 u q q + 1 p R N Z ( x ) u p d x + 1 q R N Z ( x ) u q d x μ 2 l 2 l N p ( N + α ) p 2 R N ( I α * u l ) u l d x + q δ ¯ q 2 R N V ( x ) u q d x 2 δ ¯ q R N W ( x ) u q d x .

Then, by combining (6.2) and (6.3), in view of ( V 1 ) , ( V 2 ) , and ( V 3 ) , we obtain that

Ψ ¯ u ( 0 ) = Ψ ¯ u ( 0 ) 2 l N p ( N + α ) p P V , l ( u ) = p 2 l N p ( N + α ) p u p p + ( δ ¯ q + 1 ) q ( δ ¯ q + 1 ) 2 l N p ( N + α ) p u q q + δ ¯ q q δ ¯ q 2 l N p ( N + α ) p R N V ( x ) u q d x + 1 p 2 l N p ( N + α ) p R N W ( x ) u p d x + 1 q 2 l N p ( N + α ) p 2 δ ¯ q R N W ( x ) u q d x + 1 p R N Z ( x ) u p d x + 1 q R N Z ( x ) u q d x p 2 l N p ( N + α ) p + 1 p 2 l N p ( N + α ) p σ 3 + 1 p σ 5 u p p + ( δ ¯ q + 1 ) q ( δ ¯ q + 1 ) 2 l N p ( N + α ) p + δ ¯ q 2 l N p ( N + α ) p q δ ¯ q σ 2 + 1 q 2 l N p ( N + α ) p 2 δ ¯ q σ 4 + σ 6 q u q q < 0 .

This means that u ( P ¯ c V , l ) . Thus, P c V , l = ( P ¯ c V , l ) and we complete the proof of Lemma 6.3.□

Lemma 6.4

Assume that γ , μ > 0 , p ¯ < l p α , and ( V 1 ) , ( V 2 ) , ( V 3 ) hold. For any u S c , the function Ψ ¯ u has a unique critical point s u . That is, there exists a unique s u > 0 such that s u * u P c V , l . Moreover, I V , l ( s u * u ) = max s > 0 I V , l ( s * u ) and Ψ ¯ u is strictly decreasing and concave on ( s u , + ) . In particular, s u < 0 if and only if P V , l ( u ) < 0 . And the map u S c s u R is of class C 1 .

Proof

Note that Ψ ¯ u ( s ) = P V , l ( s * u ) . Then we only need to show that Ψ ¯ u ( s ) has a unique root in R . In view of ( V 1 ) and ( V 2 ) , we have

(6.4) Ψ ¯ u ( s ) = e p s u p p + ( δ ¯ q + 1 ) e q ( δ ¯ q + 1 ) s u q q 1 p R N W ( e s x ) u p d x e q δ ¯ q s q R N W ( e s x ) u q d x + δ ¯ q e q δ ¯ q s R N V ( e s x ) u q d x μ 2 l 2 l N p ( N + α ) p e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x 1 σ 3 p e p s u p p + δ ¯ q + 1 σ 4 q δ ¯ q σ 2 e q ( δ ¯ q + 1 ) s u q q μ 2 l 2 l N p ( N + α ) p e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x .

Obviously, Ψ ¯ u ( s ) > 0 for s , which implies that there exists s 0 R such that Ψ ¯ u ( s ) is increasing on ( , s 0 ) . On the other hand, we observe that Ψ ¯ u ( s ) as s + , which yields that there exists s 1 R with s 1 > s 0 such that

(6.5) Ψ ¯ u ( s 1 ) = max s > 0 Ψ ¯ u ( s ) .

This means that Ψ ¯ u ( s 1 ) = 0 , namely, s 1 * u P c V , l . To show the uniqueness of s 1 , we supoose that there exists s 2 R satisfying s 2 * u P c V , l . Without loss of generality, we may assume that s 2 > s 1 . In virtue of Lemma 6.3, we find that Ψ ¯ u ( s 2 ) < 0 . As a consequence, there exists s 3 ( s 1 , s 2 ) such that

Ψ ¯ u ( s 3 ) = min s ( s 1 , s 2 ) Ψ ¯ u ( s ) .

It follows that Ψ ¯ u ( s 3 ) = 0 and Ψ ¯ u ( s 3 ) 0 , namely, s 3 * u P c V , l and s 3 * u ( P ¯ c V , l ) + ( P ¯ c V , l ) 0 . This is impossible by Lemma 6.3. Thus, s u = s 1 and s u R is a unique number satisfying s u * u P c V , l and I V , l ( s u * u ) = max s > 0 I V , l ( s * u ) . Moreover,

(6.6) Ψ ¯ u ( s ) < 0 s > s u .

In particular, Ψ ¯ u ( 0 ) = P V , l ( u ) < 0 is and only if s u < 0 . Next, we show that Ψ ¯ u is strictly decreasing and concave on ( s u , + ) . Indeed, from (6.6), Ψ ¯ u is strictly decreasing on ( s u , + ) . Now we claim that Ψ ¯ u ( s ) < 0 on ( s u , + ) . Clearly, it follows from ( V 3 ) that

(6.7) Ψ ¯ u ( s ) = p e p s u p p + q ( δ ¯ q + 1 ) 2 e q ( δ ¯ q + 1 ) s u q q + 1 p R N Z ( e s x ) u p d x + e q δ ¯ q s q R N Z ( e s x ) u q d x μ 2 l 2 l N p ( N + α ) p 2 e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x + q δ ¯ q 2 e q δ ¯ q s R N V ( e s x ) u q d x 2 δ ¯ q e q δ ¯ q s R N W ( e s x ) u q d x p + 1 p σ 5 e p s u p p + q ( δ ¯ q + 1 ) 2 + 1 q σ 6 + q δ ¯ q 2 σ 2 + 2 δ ¯ q σ 4 e q ( δ ¯ q + 1 ) s u q q μ 2 l 2 l N p ( N + α ) p 2 e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x .

Now based on (6.4) and (6.7), we let

f 1 ( s ) 1 σ 3 p e p s u p p + δ ¯ q + 1 σ 4 q δ ¯ q σ 2 e q ( δ ¯ q + 1 ) s u q q μ 2 l 2 l N p ( N + α ) p e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x

and

f 2 ( s ) p + 1 p σ 5 e p s u p p + q ( δ ¯ q + 1 ) 2 + 1 q σ 6 + q δ ¯ q 2 σ 2 + 2 δ ¯ q σ 4 e q ( δ ¯ q + 1 ) s u q q μ 2 l 2 l N p ( N + α ) p 2 e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x .

It is clear that f 1 and f 2 have a unique zero point. Then we suppose that f 1 ( s ¯ 1 ) = 0 and f 2 ( s ¯ 2 ) = 0 . Moreover, we find that f 1 ( s ) > 0 for s ( , s ¯ 1 ) and f 1 ( s ) < 0 for s ( s ¯ 1 , + ) , f 2 ( s ) > 0 for s ( , s ¯ 2 ) and f 2 ( s ) < 0 for s ( s ¯ 2 , + ) . Then it follows from (6.4) that Ψ ¯ u is strictly increasing on ( , s ¯ 1 ) . Combining the fact that Ψ ¯ u is strictly increasing on ( , s u ) and is strictly decreasing on ( s u , + ) , we infer that s ¯ 1 s u . Furthermore, if s ¯ 2 s u , we obtain that Ψ ¯ u ( s ) < 0 on ( s u , + ) by (6.7). Hence, we only need to prove s ¯ 2 s ¯ 1 . That is, we need to prove f 2 ( s ¯ 1 ) 0 . Indeed, since f 1 ( s ¯ 1 ) = 0 , namely,

1 σ 3 p e p s ¯ 1 u p p + δ ¯ q + 1 σ 4 q δ ¯ q σ 2 e q ( δ ¯ q + 1 ) s ¯ 1 u q q = μ 2 l 2 l N p ( N + α ) p e 2 l N p ( N + α ) p s ¯ 1 R N ( I α * u l ) u l d x ,

by ( V 1 ) , ( V 2 ) , and ( V 3 ) , we deduce that

f 2 ( s ¯ 1 ) = p + 1 p σ 5 e p s ¯ 1 u p p + q ( δ ¯ q + 1 ) 2 + 1 q σ 6 + q δ ¯ q 2 σ 2 + 2 δ ¯ q σ 4 e q ( δ ¯ q + 1 ) s ¯ 1 u q q μ 2 l 2 l N p ( N + α ) p 2 e 2 l N p ( N + α ) p s ¯ 1 R N ( I α * u l ) u l d x = p + 1 p σ 5 1 σ 3 p 2 l N p ( N + α ) p e p s ¯ 1 u p p + q ( δ ¯ q + 1 ) 2 + 1 q σ 6 + q δ ¯ q 2 σ 2 + 2 δ ¯ q σ 4 δ ¯ q + 1 σ 4 q δ ¯ q σ 2 2 l N p ( N + α ) p e q ( δ ¯ q + 1 ) s ¯ 1 u q q < 0 .

Thus, we know that Ψ ¯ u is strictly concave on ( s u , + ) .

In the last, we shall show that the map u S c s u R is of class C 1 . Clearly, based on the fact that h ( s , u ) Ψ ¯ u ( s ) is of class C 1 , h ( s u , u ) = 0 and s h ( s u , u ) = Ψ ¯ u ( s u ) < 0 , applying the implicit function theorem, we obtain that the map u S c s u R is of class C 1 . So the proof of Lemma 6.4 is completed.□

Lemma 6.5

Assume that γ , μ > 0 , p ¯ < l p α , and ( V 1 ) , ( V 2 ) hold. If c satisfies 0 < c < min { c * , c * * } , where

c * * 1 q 1 2 l γ l 2 p α γ S α p α ξ 2 l γ l 2 l γ l q ( μ K N , l , α γ l ) q 2 l γ l q 2 l γ l q p p α ( 2 l γ l q ) + 2 q l ( 1 γ l ) ,

ξ min 1 p ( 1 σ 1 ) , 1 q ( 1 σ 2 )

and c * is introduced in Lemma 6.2, then there exists μ ˆ > 0 large enough such that when μ > μ ˆ staisfying

k > ξ q μ K N , l , α γ l c 2 l ( 1 γ l ) q 2 l γ l q ,

0 < sup A ¯ k I V , l < m c V , l and u A ¯ k P V , l ( u ) > 0 ,

where A k = { u S c : u p p + u q q < k } and A ¯ k is a closure of A k .

Proof

From ( V 1 ) , (1.11), and (1.16), we derive that

I V , l ( u ) = 1 p u p p + 1 q u q q + 1 p R N V ( x ) u p d x + 1 q R N V ( x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l R N ( I α * u l ) u l d x 1 p ( 1 σ 1 ) u p p + 1 q ( 1 σ 2 ) u q q γ 2 p α S α p α c p p α μ 2 l K N , l , α u q 2 l γ l c 2 l ( 1 γ l ) .

By combining the condition 0 < c < c * * , we infer that sup A ¯ k I V , l > 0 . In addition, by ( V 1 ) , ( V 2 ) , and (1.16), one has

P V , l ( u ) = u p p + ( δ ¯ q + 1 ) u q q + δ ¯ q R N V ( x ) u q d x 1 p R N W ( x ) u p d x 1 q R N W ( x ) u q d x 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x 1 σ 3 p u p p + δ ¯ q + 1 δ ¯ q σ 2 1 q σ 4 u q q 2 l N p ( N + α ) 2 l p μ K N , l , α u q 2 l γ l c 2 l ( 1 γ l ) .

This implies that P V , l ( u ) > 0 for any u A ¯ k with k > 0 small enough. Moreover, it follows from Lemma 6.2 that we choose k small enough, and for all u A ¯ k ,

I V , l ( u ) 1 p u p p + 1 q u q q < m c V , l .

So we complete the proof of Lemma 6.5.□

Lemma 6.6

Assume that γ , μ > 0 , p ¯ < l p α , and ( V 1 ) holds. Then m c V , l < m c 0 , l .

Proof

In view of Theorems 1.10 and 1.12, we know that there exists u S c such that I 0 , l ( u ) = m c 0 , l . Then u P c 0 , l . By using Lemma 6.4, we derive that there exists a unique s u R such that s u * u P c V , l . Then by ( V 1 ) , based on Lemma 4.1, one infers that

m c V , l I V , l ( s u * u ) = I 0 , l ( s u * u ) + 1 p R N V ( e s u x ) u p d x + e q δ ¯ q s u q R N V ( e s u x ) u q d x < I 0 , l ( s u * u ) I 0 , l ( u ) .

Thus m c V , l < m c 0 , l . So the proof of Lemma 6.6 is completed.□

Lemma 6.7

Assume that γ , μ > 0 , and p ¯ < l p α . If u P c V , l is a critical point for I V , l P c V , l and ( P ¯ c V , l ) 0 = , then u is a critical point for I V , l S c .

Proof

If u P c V , l is a critical point for I V , l P c V , l , then there exist λ , ζ R such that

I V , l ( u ) + λ u p 2 u + ζ P V , l ( u ) = 0 ,

which means that

( 1 + ζ p ) Δ p u [ 1 + ζ q ( δ ¯ q + 1 ) ] Δ q u + V ( x ) u p 2 u + λ u p 2 u + ( 1 + ζ q δ ¯ q ) V ( x ) u q 2 u ζ W ( x ) u p 2 u ζ W ( x ) u q 2 u γ ( I α * u p α ) u p α 2 u 1 + 2 l N p ( N + α ) p ζ μ ( I α * u l ) u l 2 u = 0 .

Similarly, the corresponding Pohozaev identity is given by

(6.8) ( 1 + ζ p ) u p p + ( δ ¯ q + 1 ) [ 1 + ζ q ( δ ¯ q + 1 ) ] u q q + δ ¯ q ( 1 + ζ q δ ¯ q ) R N V ( x ) u q d x 1 p R N W ( x ) u p d x 1 q R N ( 1 + ζ q δ ¯ q ) W ( x ) u q d x + 1 p R N ζ Z ( x ) u p d x + 1 q R N ζ Z ( x ) u q d x δ ¯ q R N ζ W ( x ) u q d x 2 l N p ( N + α ) 2 p l μ 1 + 2 l N p ( N + α ) p ζ R N ( I α * u l ) u l d x = 0 .

On the other hand, since u P c V , l , P V , l ( u ) = 0 , namely,

(6.9) u p p + ( δ ¯ q + 1 ) u q q + δ ¯ q R N V ( x ) u q d x = 1 p R N W ( x ) u p d x + 1 q R N W ( x ) u q d x + 2 l N p ( N + α ) 2 l p μ R N ( I α * u l ) u l d x .

By combining (6.8) and (6.9), we obtain that

ζ p u p p + q ( δ ¯ q + 1 ) 2 u q q + q δ ¯ q 2 R N V ( x ) u q d x 2 δ ¯ q R N W ( x ) u q d x + 1 p R N Z ( x ) u p d x + 1 q R N Z ( x ) u q d x μ 2 l 2 l N p ( N + α ) p 2 R N ( I α * u l ) u l d x = 0 .

It follows from (6.3) that ( P ¯ c V , l ) 0 = gives that

p u p p + q ( δ ¯ q + 1 ) 2 u q q + q δ ¯ q 2 R N V ( x ) u q d x 2 δ ¯ q R N W ( x ) u q d x + 1 p R N Z ( x ) u p d x + 1 q R N Z ( x ) u q d x μ 2 l 2 l N p ( N + α ) p 2 R N ( I α * u l ) u l d x 0 .

Then ζ = 0 . So the proof of Theorem 6.7 is completed.□

Proof of Theorem 1.15

To show that there exists ( λ , u ) R + × E that solves (1.1) satisfying I V , l ( u ) = m c V , l . We shall divide the proof into three steps.

Step 1 . we show that there eixsts a couple ( λ , u ) R + × E to satisfy

Δ p u Δ q u + V ( x ) ( u p 2 u + u q 2 u ) + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u l ) u l 2 u , in R N .

Let k > 0 be defined by Lemma 6.5. Considering the augmented functional I ˜ V , l : R × E R defined by

I ˜ V , l ( s , u ) I V , l ( s * u ) = e p s p u p p + e q ( δ ¯ q + 1 ) s q u q q + 1 p R N V ( e s x ) u p d x + e q δ ¯ q s q R N V ( e s x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l e 2 l N p ( N + α ) p s R N ( I α * u l ) u l d x .

Then it is clear that I ˜ V , l is of class C 1 . Inspired by [50,51], denoting by V , l d the closed sublevel set { u S c : I V , l ( u ) d } , we introduce the minimax class

Γ { ρ = ( ρ 1 , ρ 2 ) C ( [ 0 , 1 ] , R × S c ) : ρ ( 0 ) ( 0 , A ¯ k ) , ρ ( 1 ) ( 0 , V , l 0 ) }

with the associated minimax level

m ˜ c V , l inf ρ Γ max ( s , u ) ρ ( [ 0 , 1 ] ) I ˜ V , l ( s , u ) .

Fix u S c . Since ( s * u ) p 0 + , ( s * u ) q 0 + as s and I V , l ( s * u ) as s + , we find that there exists s ˜ 0 < < 1 and s ˜ 1 > > 1 such that

ρ u : τ [ 0 , 1 ] ( 0 , ( ( 1 τ ) s ˜ 0 + τ s ˜ 1 ) * u ) R × S c

is a path in Γ . Then m ˜ c V , l is a real number. Next, for any ρ = ( ρ 1 , ρ 2 ) Γ , we consider the function

P V , l ρ : τ [ 0 , 1 ] P V , l ( ρ 1 ( τ ) * ρ 2 ( τ ) ) R .

By Lemma 6.5, since ρ 2 ( 0 ) A ¯ k , we see that P V , l ρ ( 0 ) = P V , l ( ρ 2 ( 0 ) ) > 0 . In the following, we claim that P V , l ρ ( 1 ) = P V , l ( ρ 2 ( 1 ) ) < 0 . Indeed, Note that Ψ ¯ u ( s ) > 0 for s and Ψ ¯ u ( s ) > 0 for s . Then in virtue of Lemma 6.4, we obtain that Ψ ¯ ρ 2 ( 1 ) ( s ) > 0 for s s ρ 2 ( 1 ) . Furthermore, since ρ 2 ( 1 ) V , l 0 , Ψ ¯ ρ 2 ( 1 ) ( 0 ) = I V , l ( ρ 2 ( 1 ) ) 0 , which yields that s ρ 2 ( 1 ) < 0 . Then using Lemma 6.4 again, the claim is true. On the one hand, we observe that the map τ ρ 1 ( τ ) * ρ 2 ( τ ) is continuous from [ 0 , 1 ] to E . Thus, there exists τ ρ ( 0 , 1 ) such that P V , l ρ ( τ ρ ) = 0 . That is, ρ 1 ( τ ρ ) * ρ 2 ( τ ρ ) P c V , l . This means that

max ρ ( [ 0 , 1 ] ) I ˜ V , l I ˜ V , l ( ρ ( τ ρ ) ) = I ˜ V , l ( ρ 1 ( τ ρ ) , ρ 2 ( τ ρ ) ) = I V , l ( ρ 1 ( τ ρ ) * ρ 2 ( τ ρ ) ) inf u P c V , l I V , l ( u ) = m c V , l ,

which gives that m ˜ c V , l m c V , l . On the other hand, if u P c V , l , then ρ u is a path in Γ with

I V , l ( u ) = max ρ u ( [ 0 , 1 ] ) I ˜ V , l m ˜ c V , l ,

which yields that m c V , l m ˜ c V , l . Then in view of Lemma 6.5, we derive that

m ˜ c V , l = m c V , l > sup ( A ¯ k V , l 0 ) S c I V , l = sup ( ( 0 , A ¯ k ) ( 0 , V , l 0 ) ) ( R × S c ) I ˜ V , l .

By applying Section 5 in [22], we easily find that { ρ ( [ 0 , 1 ] ) : ρ Γ } is a homotopy stable family of compact subsets of R × S c with extended closed boundary ( 0 , A ¯ k ) ( 0 , V , l 0 ) , and the superlevel set { I V , l m ˜ c V , l } is a dual set for Γ . Moreover, taking any minimizing sequence ρ n = ( ( ρ 1 ) n , ( ρ 2 ) n ) Γ for I ˜ V , l R × S c at the level m ˜ c V , l with the property that ( ρ 1 ) n = 0 and ( ρ 2 ) n ( τ ) 0 a.e. in R N for every τ [ 0 , 1 ] , there exists a sequence { ( s n , v n ) } R × S c \ ( ( 0 , A ¯ k ) ( 0 , V , l 0 ) ) such that, as n ,

  1. I ˜ V , l ( s n , v n ) m ˜ c V , l .

  2. I ˜ V , l R × S c ( s n , v n ) 0 .

  3. dist ( s n , v n ) , ( 0 , ( ρ 2 ) n ( τ ) ) 0 .

Denote u n s n * v n = e N s n p v n ( e s n x ) . By ( i ) , we obtain that

(6.10) lim n I V , l ( u n ) = lim n I V , l ( s n * v n ) = lim n I ˜ V , l ( s n , v n ) = m ˜ c V , l = m c V , l .

In addition, it follows from ( ii ) that

s I ˜ V , l ( s n , v n ) = I ˜ V , l ( s n , v n ) , ( 1 , 0 ) 0 as n ,

where

s I ˜ V , l ( s n , v n ) = e p s n v n p p + ( δ ¯ q + 1 ) e q ( δ ¯ q + 1 ) s n u q q 1 p R N W ( e s n x ) u p d x + δ ¯ q e q δ ¯ q s n R N V ( e s n x ) u q d x e q δ ¯ q s n q R N W ( e s n x ) u q d x μ [ 2 l N p ( N + α ) ] 2 l p e 2 l N p ( N + α ) p s n R N ( I α * u l ) u l d x .

Obviously,

(6.11) P V , l ( u n ) = P V , l ( s n * v n ) = s I ˜ V , l ( s n , v n ) 0 as n .

Setting w n T u n z E : R N u n p 2 u n z d x = 0 , by direct calculation, we deduce that

I V , l ( u n ) , w n = R N u n p 2 u n w n d x + R N u n q 2 u n w n d x + R N V ( x ) u n p 2 u n w n d x + R N V ( x ) u n q 2 u n w n d x γ R N ( I α * u n p α ) u n p α 2 u n w n d x μ R N ( I α * u n l ) u n l 2 u n w n d x = e p s n R N e ( N + p ) s n p v n p 2 v n w n ( e s n x ) d x + e q ( δ ¯ q + 1 ) s n R N e ( N + p ) s n p v n q 2 v n w ( e s n x ) d x + R N e N s n p V ( e s n x ) v n p 2 v n w n ( e s n x ) d x + e q δ ¯ q s n R N e N s n p V ( e s n x ) v n q 2 v n w n ( e s n x ) d x γ R N e N s n p ( I α * v n p α ) v n p α 2 v n w n ( e s n x ) d x μ e 2 l N p ( N + α ) p s n R N e N s n p ( I α * v n l ) v n l 2 v n w ( e s n x ) d x = e p s n R N v n p 2 v n w ˜ n d x + e q ( δ ¯ q + 1 ) s n R N v n q 2 v n w ˜ n d x + R N V ( e s n x ) v n p 2 v n w ˜ n d x + e q δ ¯ q s n R N V ( e s n x ) v n q 2 v n w ˜ n d x γ R N ( I α * v n p α ) v n p α 2 v n w ˜ n d x μ e 2 l N p ( N + α ) p s n R N ( I α * v n l ) v n l 2 v n w ˜ n d x ,

where w ˜ n e N s n p w n ( e s n x ) . This gives that

(6.12) I V , l ( u n ) , w n = I ˜ V , l ( s n , v n ) , ( 0 , w ˜ n ) .

Next we show that

(6.13) ( 0 , w ˜ n ) T ˜ ( s n , v n ) ( z 1 , z 2 ) R × E : R N v n p 2 v n z 2 d x = 0 .

Indeed,

( 0 , w ˜ n ) T ˜ ( s n , v n ) R N v n p 2 v n w ˜ n d x = 0 R N v n p 2 v n e N s n p w n ( e s n x ) d x = 0 R N e N s n p v n ( e s n x ) p 2 e N s n p v n ( e s n x ) w n ( x ) d x = 0 R N u n p 2 u n w n ( x ) d x w n T u n .

Hence, in virtue of ( ii ) , (6.12), and (6.13), one infers that as n ,

I V , l ( u n ) , w n 0 for all w n T u n ,

namely,

(6.14) I V , l S c ( u n ) 0 as n .

In addition, in view of ( iii ) , we find that s n is bounded from above and from below. Furthermore, using (6.10), (6.11), and (6.14), we see that { u n } is a Palais-Smale sequence for I V , l S c at the level m ˜ c V , l = m c V , l satisfying

(6.15) I V , l ( u n ) m c V , l , I V , l S c ( u n ) 0 and P V , l ( u n ) 0 as n .

Then on the basis of the proof of Lemma 6.2, we know that { u n } is bounded in E . Hence, up to a subsequence, there is u E such that u n u in E ; u n u in L loc ν ( R N ) ( ν ( p , p * ) ) ; u n ( x ) u ( x ) a.e. on R N . It follows from (6.15) and the Lagrange multipliers rule, there exists λ n R such that

R N u n p 2 u n ψ d x + R N u n q 2 u n ψ d x + R N V ( x ) u n p 2 u n ψ d x + R N V ( x ) u n q 2 u n ψ d x + λ n u n p 2 u n ψ = γ R N ( I α * u n p α ) u n p α 2 u n ψ d x + μ R N ( I α * u n l ) u n l 2 u n ψ d x + o n ( 1 ) ψ E ,

for every ψ E . In particular, we take ψ = u n and it holds that

(6.16) λ n c p = γ R N ( I α * u n p α ) u n p α d x + μ R N ( I α * u n l ) u n l d x u n p p u n q q R N V ( x ) u n p d x R N V ( x ) u n q d x + o n ( 1 ) ,

which along with the boundedness of { u n } , ( V 1 ) , Lemma 1.1, the Sobolev embedding theorem yield that { λ n } is bounded in R . Then there exists λ R such that λ n λ as n . Hence, ( λ , u ) R × E satisfies

Δ p u Δ q u + V ( x ) ( u p 2 u + u q 2 u ) + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u l ) u l 2 u , in R N .

In the following, we claim that λ > 0 . In fact, combining (6.16) and the fact that P V , l ( u n ) 0 , namely,

u n p p + ( δ ¯ q + 1 ) u n q q + δ ¯ q R N V ( x ) u n q d x = 1 p R N W ( x ) u n p d x + 1 q R N W ( x ) u n q d x + 2 l N p ( N + α ) 2 l p μ R N ( I α * u n l ) u n l d x + o n ( 1 ) ,

one has

λ n c p = γ R N ( I α * u n p α ) u n p α d x + 1 2 l N ( N + α ) 2 l p μ R N ( I α * u n l ) u n l d x + δ ¯ q u n q q 1 p R N W ( x ) u n p d x 1 q R N W ( x ) u n q d x R N V ( x ) u n p d x R N V ( x ) u n q d x + o n ( 1 ) .

Then in view of ( V 4 ) and Fatou’s lemma, we obtain that

λ c p liminf n + γ R N ( I α * u n p α ) u n p α d x + 1 2 l N ( N + α ) 2 l p μ R N ( I α * u n l ) u n l d x + δ ¯ q u n q q ] γ R N ( I α * u p α ) u p α d x + 1 2 l N ( N + α ) 2 l p μ R N ( I α * u l ) u l d x + δ ¯ q u q q .

This means that λ 0 . Moreover, u 0 if and only if λ 0 . So we shall show that u 0 . Assume by contradiction that u = 0 . Then it follows from ( V 1 ) and ( V 2 ) that

m c V , l = I V , l ( u n ) = I 0 , l ( u n ) + o n ( 1 ) , P V , l ( u n ) = P 0 , l ( u n ) + o n ( 1 ) ,

which along with the fact that P V , l ( u n ) 0 as n yields that P 0 , l ( u n ) 0 as n . Then based on Lemma 4.1, one has for any n N , there exists a unique t n > 0 with t n 0 as n such that t n * u n P c 0 , l . Therefore,

m c 0 , l I 0 , l ( t n * u n ) = m c V , l + o n ( 1 ) ,

which contradicts with Lemma 6.6. This give that u 0 and λ > 0 . To sum up, there exists ( λ , u ) R + × E satisfies

Δ p u Δ q u + V ( x ) ( u p 2 u + u q 2 u ) + λ u p 2 u = γ ( I α * u p α ) u p α 2 u + μ ( I α * u l ) u l 2 u .

As a consequence, P V , l ( u ) = 0 .

Step 2 . We show that u S c . Let u p = c ¯ 1 ( 0 , c ] . Then u P c ¯ 1 V , l . Similar to Lemma 6.2, we obtain I V , l ( u ) > 0 . If c c ¯ 1 , denoting c ¯ 2 p = c p c ¯ 1 p ( 0 , c p ) and ω n u n u 0 in E as n , then ω n p = c ¯ 2 > 0 . By using Brezis-Lieb Lemma in [12], the facts that P V , l ( u ) = 0 , P V , l ( u n ) 0 as n , ( V 1 ) and ( V 2 ) , we easily obtain

(6.17) I V , l ( u n ) = I 0 , l ( ω n ) + I V , l ( u ) + o n ( 1 ) , P V , l ( u n ) = P 0 , l ( ω n ) + o n ( 1 ) = o n ( 1 ) .

Hence, applying Lemma 4.1, we know that for any n N , there exists a unique t ¯ n > 0 with t ¯ n 0 as n such that t ¯ n * ω n P c ¯ 2 0 , l , which along with (6.17) and the fact that I V , l ( u ) > 0 yields that

m c ¯ 2 0 , l I 0 , l ( t ¯ n * ω n ) = I 0 , l ( ω n ) + o n ( 1 ) = m c V , l I V , l ( u ) + o n ( 1 ) .

Then in view of Lemma 6.6, one has m c ¯ 2 0 , l m c V , l < m c 0 , l , which contradicts with Theorem 1.14. So c = c ¯ 1 . That is, u S c .

Step 3 . We show that I V , l ( u ) = m c V , l . Since u S c and u n u in L p ( R ) , we have as n , u n u in L p ( R N ) . Then by (1.15) and (1.16), we infer that

(6.18) u n u in L ν ( R N ) with ν [ p , p * ) .

From u P c V , l , we deduce that I V , l ( u ) m c V , l . Then combining the fact that P V , l ( u ) = 0 , Fatou’s Lemma, (6.18), ( V 1 ) , and ( V 2 ) , it holds that

m c V , l I V , l ( u ) p 2 l N p ( N + α ) P V , l ( u ) = 1 p p 2 l N p ( N + α ) u p p + 1 q p ( δ ¯ q + 1 ) 2 l N p ( N + α ) u q q + 1 p R N V ( x ) u p d x + 1 q p δ ¯ q 2 l N p ( N + α ) R N V ( x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x + 1 2 l N p ( N + α ) R N W ( x ) u p d x + p q [ 2 l N p ( N + α ) ] R N W ( x ) u q d x liminf n 1 p p 2 l N p ( N + α ) u n p p + 1 q p ( δ ¯ q + 1 ) 2 l N p ( N + α ) u n q q + 1 p R N V ( x ) u n p d x + 1 q p δ ¯ q 2 l N p ( N + α ) R N V ( x ) u n q d x γ 2 p α R N ( I α * u n p α ) u n p α d x + 1 2 l N p ( N + α ) R N W ( x ) u n p d x + p q [ 2 l N p ( N + α ) ] R N W ( x ) u n q d x = liminf n I V , l ( u n ) p 2 l N p ( N + α ) P V , l ( u n ) = lim n I V , l ( u n ) = m c V , l .

This gives that I V , l ( u n ) = m c V , l .

In the last, we observe that u p u p and u q u q . Then I V , l ( u ) I V , l ( u ) and P V , l ( u ) P V , l ( u ) = 0 . By applying Lemma 6.4, there exists s u 0 such that s u * u P c V , l . Thus,

m c V , l I V , l ( s u * u ) = e p s u p u p p + e q ( δ ¯ q + 1 ) s u q u q q + 1 p R N V ( e s u x ) u p d x + e q δ ¯ q s u q R N V ( e s u x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l e 2 l N p ( N + α ) p s u R N ( I α * u l ) u l d x e p s u p u p p + e q ( δ ¯ q + 1 ) s u q u q q + 1 p R N V ( e s u x ) u p d x + e q δ ¯ q s u q R N V ( e s u x ) u q d x γ 2 p α R N ( I α * u p α ) u p α d x μ 2 l e 2 l N p ( N + α ) p s u R N ( I α * u l ) u l d x = I V , l ( s u * u ) I V , l ( u ) = m c V , l ,

which implies that u p = u p and u q = u q . Then I V , l ( u ) = I V , l ( u ) = m c V , l and P V , l ( u ) = P V , l ( u ) = 0 . Hence, we let u u and u is a nonnegative function satisfying (1.1) for some λ R + . Similar to the discussion of Lemma 3.1 in [59], by applying the regularity conclusions in [24], we have u L ( R N ) C loc 1 , υ ( R N ) for some υ ( 0 , 1 ) . Consequently, by using the Harnack’s inequality in [53], we conclude that u > 0 . So the proof of Theorem 1.15 is completed.□

  1. Funding information: The research of Li Cai is partially supported by the Postgraduate Research and Practice Innovation Program of Jiangsu Province (No. KYCX21_0076). Li Cai would like to thank the China Scholarship Council for its support (No. 202206090124) and the Embassy of the People’s Republic of China in Romania. The research of Fubao Zhang is partially supported by National Natural Science Foundation of China (No. 11671077) and National Scientific Research Program Cultivation Fund of Chengxian College of Southeast University (No. 2022NCF008).

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and consented to its submission to the journal, reviewed all the results and approved the final version of the manuscript. The first author Cai prepared the manuscript, and the corresponding author Zhang prepared and checked it.

  3. Conflict of interest: The authors state no conflict of interest.

References

[1] R. A. Adams, Sobolev Spaces. vol. 65, Academic Press, New York, 1975. Search in Google Scholar

[2] M. Agueh, Sharp Gagliardo-Nireberg inequalities via p-Laplacian type equations, NoDEA Nonlinear Differ. Equ. Appl. 15 (2008), 457–472. 10.1007/s00030-008-7021-4Search in Google Scholar

[3] C. O. Alves and G. M. Figueiredo, Multiplicity and concentration of positive solutions for a class of quasilinear problems, Adv. Nonlinear Stud. 11 (2011), 265–294. 10.1515/ans-2011-0203Search in Google Scholar

[4] C. O. Alves and M. Yang, Multiplicity and concentration of solutions for a quasilinear Choquard equation, J. Math. Phys 55 (2014), 061502. 10.1063/1.4884301Search in Google Scholar

[5] A. Ambrosetti and A. Malchiodi, Perturbation Methods and Semilinear Elliptic Problems on RN, Progress in Mathematics, vol. 240. Birkhäuser, Basel, 2006. 10.1007/3-7643-7396-2Search in Google Scholar

[6] A. Bahrouni, V. D. Rădulescu, and D. D. Repovš, Double phase transonic flow problems with variable growth: nonlinear patterns and stationary waves, Nonlinearity 32 (2019), 2481–2495. 10.1088/1361-6544/ab0b03Search in Google Scholar

[7] L. Baldelli and T. Yang, Normalized solutions to a class of (2, q)-Laplacian equations, 2022, arXiv: 2212.14873. Search in Google Scholar

[8] J. Bellazzini, L. Jeanjean, and T. Luo, Existence and instability of standing waves with prescribed norm for a class of Schrödinger-Poisson equations, Proc. Lond. Math. Soc. 107 (2013), 303–339. 10.1112/plms/pds072Search in Google Scholar

[9] V. Benci, P. d’Avenia, D. Fortunato, and L. Pisani, Solitons in several space dimensions: Derrick’s problem and infinitely many solutions, Arch. Ration. Mech. Anal. 154 (2000), 297–324. 10.1007/s002050000101Search in Google Scholar

[10] H. Berestycki and P. L. Lions, Nonlinear scalar field equations I: existence of a ground state, Arch. Rat. Mech. Anal. 82 (1983), 313–346. 10.1007/BF00250555Search in Google Scholar

[11] D. Bonheure, P. d’Avenia, and A. Pomponio, On the electrostatic Born-Infeld equation with extended charges, Commun. Math. Phys. 346 (2016), 877–906. 10.1007/s00220-016-2586-ySearch in Google Scholar

[12] H. Brezis and E. H. Lieb, A relation between pointwise convergence of functions and convergence of functionals, Proc. Amer. Math. Soc. 88 (1983), 486–490. 10.1090/S0002-9939-1983-0699419-3Search in Google Scholar

[13] L. Cai, N. S. Papageorgiou, and V. D. Rădulescu, Multiple and nodal solutions for parametric Dirichlet equations driven by the double-phase differential operator, Complex Anal. Oper. Theory 17 (2023), 62. 10.1007/s11785-023-01379-zSearch in Google Scholar

[14] L. Cai and F. Zhang, Normalized solutions of mass supercritical Kirchhoff equation with potential, J. Geom. Anal. 33 (2023), 107. 10.1007/s12220-022-01148-ySearch in Google Scholar

[15] D. Cao, H. Jia, and X. Luo, Standing waves with prescribed mass for the Schrödinger equations with van der Waals type potentials, J. Differ. Equ. 276 (2021), 228–263. 10.1016/j.jde.2020.12.016Search in Google Scholar

[16] T. Cazenave and P. L. Lions, Orbital stability of standing waves for some nonlinear Schrödinger equations, Commun. Math. Phys. 85 (1982), 549–561. 10.1007/BF01403504Search in Google Scholar

[17] S. Cingolani and L. Jeanjean, Stationary waves with prescribed L2-norm for the planar Schrödinger-Poisson system, Siam J. Math. Anal. 51 (2019), 3533–3568. 10.1137/19M1243907Search in Google Scholar

[18] M. del Pino and P. L. Felmer, Spike-layered solutions of singularly perturbed elliptic problems in a degenerate setting, Indiana Univ. Math. J. 48 (1999), 883–898. 10.1512/iumj.1999.48.1596Search in Google Scholar

[19] M. del Pino, M. Kowalczyk, and J. Wei, Concentration on curves for nonlinear Schrödinger equations, Commun. Pure Appl. Math. 60 (2007), 113–146. 10.1002/cpa.20135Search in Google Scholar

[20] D. J. Frantzeskakis, Dark solitons in atomic Bose-Einstein condensates: from theory to experiments, J. Phys. A Math. Theor. 43 (2010), 213001. 10.1088/1751-8113/43/21/213001Search in Google Scholar

[21] L. Gasiński and P. Winkert, Sign changing solution for a double-phase problem with nonlinear boundary condition via the Nehari manifold, J. Differ. Equ. 274 (2021), 1037–1066. 10.1016/j.jde.2020.11.014Search in Google Scholar

[22] N. Ghoussoub, Duality and Perturbation Methods in Critical Point Theory, Cambridge Tracts in Mathematicss, vol. 107, Cambridge University Press, Cambridge, 1993. 10.1017/CBO9780511551703Search in Google Scholar

[23] L. Gu, X. Zeng, and H. Zhou, Eigenvalue problem for a p-Laplacian equation with trapping potentials, Nonlinear Anal. 148 (2017), 212–227. 10.1016/j.na.2016.10.002Search in Google Scholar

[24] C. He and G. Li, The regularity of weak solutions to nonlinear scalar field elliptic equations containing p&q-Laplacians, Ann. Acad. Sci. Fenn. Math. 33 (2006), 337–371. Search in Google Scholar

[25] H. Jia and X. Luo, Prescribed mass standing waves for energy critical Hartree equations, Calc. Var. Partial Differ. Equ. 62 (2023), 71. 10.1007/s00526-022-02416-zSearch in Google Scholar

[26] G. Li and S. Yan, Eigenvalue problems for quasilinear elliptic-equations on RN, Commun. Partial. Differ. Equ. 14 (1991), 1291–1414. Search in Google Scholar

[27] G. Li and H. Ye, The existence of positive solutions with prescribed L2-norm for nonlinear Choquard equations, J. Math. Phys. 55 (2014), 121501. 10.1063/1.4902386Search in Google Scholar

[28] Q. Li, J. Nie, and W. Zhang, Existence and asymptotics of normalized ground states for a Sobolev critical Kirchhoff equation, J. Geom. Anal. 33 (2023), 126. 10.1007/s12220-022-01171-zSearch in Google Scholar

[29] Y. Li and L. Nirenberg, The Dirichlet problem for singularly perturbed elliptic equations, Commun. Pure Appl. Math. 51 (1998), 1445–1490. 10.1002/(SICI)1097-0312(199811/12)51:11/12<1445::AID-CPA9>3.3.CO;2-QSearch in Google Scholar

[30] E. H. Lieb, Existence and uniqueness of the minimizing solution of Choquard’s nonlinear equation, Stud. Appl. Math. 57 (1977), 93–105. 10.1002/sapm197757293Search in Google Scholar

[31] E. H. Lieb and M. Loss, Analysis, Grad. Stud. Math., AMS, Providence, Rhode island, 2001. Search in Google Scholar

[32] P. L. Lions, The Choquard equation and related questions, Nonlinear Anal. 4 (1980), 1063–1072. 10.1016/0362-546X(80)90016-4Search in Google Scholar

[33] P. L. Lions, The concentration-compactness principle in the calculus of variations. The locally compact case, part 2, Ann. Inst. H. Poincareeee Anal. Non Linéaire 1 (1984), 223–283. 10.1016/s0294-1449(16)30422-xSearch in Google Scholar

[34] X. Luo, Normalized standing waves for the Hartree equations, J. Differ. Equ. 267 (2019), 4493–4524. 10.1016/j.jde.2019.05.009Search in Google Scholar

[35] L. Ma and L. Zhao, Classification of positive solitary solutions of the nonlinear Choquard equation, Arch. Ration. Mech. Anal. 195 (2010), 455–467. 10.1007/s00205-008-0208-3Search in Google Scholar

[36] B. Malomed, Multi-component Bose-Einstein condensates: theory, in: P.G. Kevrekidis, D.J. Frantzeskakis, R. Carretero-Gonzalez (Eds.), Emergent Nonlinear Phenomena in Bose-Einstein Con-densation, Springer-Verlag, Berlin, 2008, pp. 287–305. 10.1007/978-3-540-73591-5_15Search in Google Scholar

[37] P. Marcellini, Regularity of minimizers of integrals of the calculus of variations with nonstandard growth conditions, Arch. Ration. Mech. Anal. 105 (1989), 267–284. 10.1007/BF00251503Search in Google Scholar

[38] P. Marcellini, Regularity and existence of solutions of elliptic equations with (p,q)-growth conditions, J. Differ. Equ. 90 (1991), 1–30. 10.1016/0022-0396(91)90158-6Search in Google Scholar

[39] G. Mingione and V. D. Rădulescu, Recent developments in problems with nonstandard growth and nonuniform ellipticity, J. Math. Anal. Appl. 501 (2021), 125197. 10.1016/j.jmaa.2021.125197Search in Google Scholar

[40] V. Moroz and J. Van Schaftingen, Groundstates of nonlinear Choquard equations: Existence, qualitative properties and decay asymptotics, J. Funct. Anal. 265 (2013), 153–184. 10.1016/j.jfa.2013.04.007Search in Google Scholar

[41] V. Moroz and J. Van Schaftingen, Existence of groundstates for a class of nonlinear Choquard equations, Trans. Am. Math. Soc. 367 (2015), 6557–6579. 10.1090/S0002-9947-2014-06289-2Search in Google Scholar

[42] V. Moroz and J. Van Schaftingen, Semi-classical states for the Choquard equation, Calc. Var. Partial Differ. Equ. 52 (2015), 199–235. 10.1007/s00526-014-0709-xSearch in Google Scholar

[43] D. Mugnai and N. S. Papageorgiou, Wangas multiplicity result for superlinear (p,q)-equations without the Ambrosetti-Rabinowitz condition, Trans. Am. Math. Soc. 366 (2014), 4919–4937. 10.1090/S0002-9947-2013-06124-7Search in Google Scholar

[44] W. Ni and J. Wei, On the location and profile of spike-layer solutions to singularly perturbed semilinear Dirichlet problems, Commun. Pure Appl. Math. 48 (1995), 731–768. 10.1002/cpa.3160480704Search in Google Scholar

[45] L. Nirenberg, On elliptic partial differential equations, Il principio di minimo e sue applicazioni alle equazioni funzionali, Springer, 2011, pp. 1–48. 10.1007/978-3-642-10926-3_1Search in Google Scholar

[46] N. S. Papageorgiou, V. D. Rădulescu, and D. D. Repovš, Existence and multiplicity of solutions for double-phase Robin problems, Bull. Lond. Math. Soc. 52 (2022), 546–560. 10.1112/blms.12347Search in Google Scholar

[47] N. S. Papageorgiou, V. D. Rădulescu, and W. Zhang, Global existence and multiplicity for nonlinear Robin eigenvalue problems, Results Math. 78 (2023), 133. 10.1007/s00025-023-01912-8Search in Google Scholar

[48] S. Pekar, Untersuchungüber die Elektronentheorie der Kristalle, Akademie Verlag, Berlin, 1954. 10.1515/9783112649305Search in Google Scholar

[49] R. Penrose, On gravityas role in quantum state reduction, Gen. Relativ. Gravitat. 28 (1996), 581–600. 10.1007/BF02105068Search in Google Scholar

[50] N. Soave, Normalized ground states for the NLS equation with combined nonlinearities, J. Differ. Equ. 269 (2020), 6941–6987. 10.1016/j.jde.2020.05.016Search in Google Scholar

[51] N. Soave, Normalized ground states for the NLS equation with combined nonlinearities: The Sobolev critical case, J. Funct. Anal. 279(2020), 108610. 10.1016/j.jfa.2020.108610Search in Google Scholar

[52] G. Tarantello, On nonhomogeneous elliptic equations involving critical Sobolev exponent, Ann. Inst. H. Poincaré Anal. Non Linéaire 9 (1992), 281–304. 10.1016/s0294-1449(16)30238-4Search in Google Scholar

[53] N. S. Trudinger, On Harnack type inequalities and their application to quasilinear elliptic equations, Commun. Pure Appl. Math. 20 (1967), 721–747. 10.1002/cpa.3160200406Search in Google Scholar

[54] M. Willem, Functional analysis: Fundamentals and applications, Cornerstones, Vol. XIV, Birkhäuser, Basel, 2013. 10.1007/978-1-4614-7004-5Search in Google Scholar

[55] S. Yao, H. Chen, V. D. Rădulescu, and J. Sun, Normalized solutions for lower critical Choquard equations with critical Sobolev perturbation, Siam J. Math. Anal. 54 (2022), 3696–3723. 10.1137/21M1463136Search in Google Scholar

[56] H. Ye, Mass minimizers and concentration for nonlinear Choquard equations in RN, Topol. Methods Nonlinear Anal. 48 (2016), 393–417. 10.12775/TMNA.2016.066Search in Google Scholar

[60] J. Zhang and W. Zhang, Semiclassical states for coupled nonlinear Schrödinger system with competing potentials, J. Geom. Anal. 32 (2022), 114. 10.1007/s12220-022-00870-xSearch in Google Scholar

[58] J. Zhang, W. Zhang, and V. D. Rădulescu, Double phase problems with competing potentials: concentration and multiplication of ground states, Math. Z. 301 (2022), 4037–4078. 10.1007/s00209-022-03052-1Search in Google Scholar

[59] W. Zhang, J. Zhang, and V. D. Rădulescu, Concentrating solutions for singularly perturbed double-phase problems with nonlocal reaction, J. Differ. Equ. 347 (2023), 56–103. 10.1016/j.jde.2022.11.033Search in Google Scholar

[60] Z. Zhang and Z. Zhang, Normalized solutions to p-Laplacian equations with combined nonlinearities, Nonlinearity 35 (2022), 5621–5663. 10.1088/1361-6544/ac902cSearch in Google Scholar

[61] V. V. Zhikov, On Lavrentiev’s phenomenon, Russ. J. Math. Phys. 3 (1995), 249–269. Search in Google Scholar

[62] V. V. Zhikov, S. M. Kozlov, and O. A. Oleinik, Homogenization of Differential Operators and Integral Functionals, Springer, Berlin, 1994. 10.1007/978-3-642-84659-5Search in Google Scholar

Received: 2023-05-22
Revised: 2023-08-26
Accepted: 2024-06-10
Published Online: 2024-07-25

© 2024 the author(s), published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Regular Articles
  2. Existence of normalized peak solutions for a coupled nonlinear Schrödinger system
  3. Orbital stability of the trains of peaked solitary waves for the modified Camassa-Holm-Novikov equation
  4. Global boundedness in a two-dimensional chemotaxis system with nonlinear diffusion and singular sensitivity
  5. Existence and uniqueness of solution for a singular elliptic differential equation
  6. The bounded variation capacity and Sobolev-type inequalities on Dirichlet spaces
  7. Vanishing and blow-up solutions to a class of nonlinear complex differential equations near the singular point
  8. Existence, uniqueness, localization and minimization property of positive solutions for non-local problems involving discontinuous Kirchhoff functions
  9. Concentration phenomena for a fractional relativistic Schrödinger equation with critical growth
  10. Beyond the classical strong maximum principle: Sign-changing forcing term and flat solutions
  11. Monotonicity of solutions for parabolic equations involving nonlocal Monge-Ampère operator
  12. On a nonlinear Robin problem with an absorption term on the boundary and L1 data
  13. Multiple solutions for the quasilinear Choquard equation with Berestycki-Lions-type nonlinearities
  14. Gradient estimates for a class of higher-order elliptic equations of p-growth over a nonsmooth domain
  15. Global existence and decay estimates of the classical solution to the compressible Navier-Stokes-Smoluchowski equations in ℝ3
  16. Global existence and finite-time blowup for a mixed pseudo-parabolic r(x)-Laplacian equation
  17. Multiple positive solutions for a class of concave-convex Schrödinger-Poisson-Slater equations with critical exponent
  18. A minimization problem with free boundary for p-Laplacian weakly coupled system
  19. Multiplicity of semiclassical solutions for a class of nonlinear Hamiltonian elliptic system
  20. k-convex solutions for multiparameter Dirichlet systems with k-Hessian operator and Lane-Emden type nonlinearities
  21. Infinitely many solutions for Hamiltonian system with critical growth
  22. On optimal control in a nonlinear interface problem described by hemivariational inequalities
  23. Variational–hemivariational system for contaminant convection–reaction–diffusion model of recovered fracturing fluid
  24. Potential and monotone homeomorphisms in Banach spaces
  25. Critical fractional Schrödinger-Poisson systems with lower perturbations: the existence and concentration behavior of ground state solutions
  26. Supercritical Hénon-type equation with a forcing term
  27. Concentration of blow-up solutions for the Gross-Pitaveskii equation
  28. Mountain-pass-type solutions for Schrödinger equations in R2 with unbounded or vanishing potentials and critical exponential growth nonlinearities
  29. Regularity for critical fractional Choquard equation with singular potential and its applications
  30. Double phase anisotropic variational problems involving critical growth
  31. Normalized solutions of NLS equations with mixed nonlocal nonlinearities
  32. Nontrivial solutions for resonance quasilinear elliptic systems
  33. Standing waves for Choquard equation with noncritical rotation
  34. Low regularity conservation laws for Fokas-Lenells equation and Camassa-Holm equation
  35. Modified quasilinear equations with strongly singular and critical exponential nonlinearity
  36. Limit profiles and the existence of bound-states in exterior domains for fractional Choquard equations with critical exponent
  37. Nests of limit cycles in quadratic systems
  38. Regularity of minimizers for double phase functionals of borderline case with variable exponents
  39. Boundedness, existence and uniqueness results for coupled gradient dependent elliptic systems with nonlinear boundary condition
  40. Ground state solutions for magnetic Schrödinger equations with polynomial growth
  41. Nonoccurrence of Lavrentiev gap for a class of functionals with nonstandard growth
  42. Dynamics for wave equations connected in parallel with nonlinear localized damping
  43. Boussinesq's equation for water waves: Asymptotics in Sector I
  44. Optimal global second-order regularity and improved integrability for parabolic equations with variable growth
  45. Normalized solutions of Schrödinger equations involving Moser-Trudinger critical growth
  46. Normalized solutions for the double-phase problem with nonlocal reaction
  47. Normalized solutions for Sobolev critical fractional Schrödinger equation
  48. Well-posedness of Cauchy problem of fractional drift diffusion system in non-critical spaces with power-law nonlinearity
  49. Improved results on planar Klein-Gordon-Maxwell system with critical exponential growth
  50. Existence and multiplicity of solutions for a new p(x)-Kirchhoff equation
  51. Quasiconvex bulk and surface energies: C1,α regularity
  52. Time decay estimates of solutions to a two-phase flow model in the whole space
  53. Bounds for the sum of the first k-eigenvalues of Dirichlet problem with logarithmic order of Klein-Gordon operators
  54. The properties of a new fractional g-Laplacian Monge-Ampère operator and its applications
  55. A fractional profile decomposition and its application to Kirchhoff-type fractional problems with prescribed mass
  56. Cauchy problem for a non-Newtonian filtration equation with slowly decaying volumetric moisture content
  57. Multiplicity of normalized semi-classical states for a class of nonlinear Choquard equations
  58. The second Yamabe invariant with boundary
  59. Peaked solitary waves and shock waves of the Degasperis-Procesi-Kadomtsev-Petviashvili equation
  60. Normalized solutions for the Choquard equations with critical nonlinearities
  61. Boundedness and long-time behavior in a parabolic-elliptic system arising from biological transport networks
  62. Initial boundary value problem and exponential stability for the planar magnetohydrodynamics equations with temperature-dependent viscosity
  63. Nonexistence of mean curvature flow solitons with polynomial volume growth immersed in certain semi-Riemannian warped products
  64. Analysis of a vector-borne disease model with vector-bias mechanism in advective heterogeneous environment
  65. Normalized solutions for the Kirchhoff equation with combined nonlinearities in ℝ4
  66. Nonexistence of the compressible Euler equations with space-dependent damping in high dimensions
  67. Multiplicity of solutions for a nonhomogeneous quasilinear elliptic equation with concave-convex nonlinearities
  68. On semilinear inequalities involving the Dunkl Laplacian and an inverse-square potential outside a ball
  69. Besov regularity for the elliptic p-harmonic equations in the non-quadratic case
  70. Uniqueness and nondegeneracy of ground states for Δ u + u = ( I α u 2 ) u in R 3 when α is close to 2
  71. Existence of solutions for a class of quasilinear Schrödinger equations with Choquard-type nonlinearity
  72. Weighted Hardy-Adams inequality on unit ball of any even dimension
  73. Existence and regularity for a p-Laplacian problem in ℝN with singular, convective, and critical reaction
  74. Temporal periodic solutions of non-isentropic compressible Euler equations with geometric effects
  75. Nodal solutions for a zero-mass Chern-Simons-Schrödinger equation
  76. The modified quasi-boundary-value method for an ill-posed generalized elliptic problem
  77. Nonlocal heat equations with generalized fractional Laplacian
  78. Choquard equations with recurrent potentials
  79. Local and global well-posedness of the Maxwell-Bloch system of equations with inhomogeneous broadening
  80. The Riemann problem for two-layer shallow water equations with bottom topography
  81. Global stability and asymptotic profiles of a partially degenerate reaction diffusion Cholera model with asymptomatic individuals
  82. On Kirchhoff-Schrödinger-Poisson-type systems with singular and critical nonlinearity
  83. Energy-variational solutions for viscoelastic fluid models
  84. Stability on 3D Boussinesq system with mixed partial dissipation
  85. Existence and multiplicity results for non-autonomous second-order Hamiltonian systems
  86. Erratum
  87. Erratum to “Normalized solutions for the Kirchhoff equation with combined nonlinearities in ℝ4
Downloaded on 9.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/anona-2024-0026/html
Scroll to top button