Home Mathematics Efficient fixed-point iteration for generalized nonexpansive mappings and its stability in Banach spaces
Article Open Access

Efficient fixed-point iteration for generalized nonexpansive mappings and its stability in Banach spaces

  • Danish Ali , Aftab Hussain , Erdal Karapinar EMAIL logo and Prasit Cholamjiak
Published/Copyright: December 31, 2022

Abstract

The aim of this article is to design a new iteration process for solving certain fixed-point problems. In particular, we prove weak and strong convergence theorems for generalized nonexpansive mappings in the framework of uniformly convex Banach spaces. In addition, we discuss the stability of the solution under mild conditions. Further, we provide some numerical examples to indicate that the proposed method works properly.

MSC 2010: 47H09; 47H10

1 Introduction and preliminaries

In the last few decades, metric fixed-point theory is one of the hot topics for researchers in mathematics and applied sciences due to its wide application potential in nonlinear systems. The power of the metric fixed-point theory is to combine functional analysis, topology, and geometry, in a unique way. Accordingly, the problems in qualitative science (engineering, biology, chemistry, economics, technology, game theory, computer science, etc.) can be transformed and solved in the context of metric fixed-point theory. The pioneering work of the theory was announced by Banach in 1922, which guarantees both the existence and uniqueness of the fixed point. Indeed, it also shows a way to obtain the desired fixed point. Notice that finding a fixed point is equivalent to saying that the transferred real-world problem has a unique solution.

On the basis of this motivation, in the last few decades, several researchers have been investigating the existence (and if possible, the uniqueness) of a fixed point of distinct operators in the setting of various spaces. We emphasize that the existence of a fixed point and finding the existence fixed point are two different tasks. It is clear that the second task is more difficult one. For this reason, for finding a fixed point, several distinct iteration processes were defined and studied. Among all, we count the most interesting and useful iteration as follows: Mann iteration process [1], Ishikawa iteration process [2], K -iteration process [3], M -iteration process [4], K -iteration process [5], M -iteration process [6], J-iteration process [7], D -iteration process [8], and its error in [9]; see also, Agarwal et al. [10], Noor [11], Abbas and Nazir [12], and Ullah et al. [13].

Motivated by the aforementioned facts, in this article, we introduce a new iteration process, namely, D -plus iteration process. In addition, we prove its stability under suitable conditions. We present a comparison of the proposed iteration process with S -iteration process [10] and Picard- S iteration process [3]. We conclude that our method can outperform them in terms of number of iterations. Finally, we prove weak and strong convergence theorems for Suzuki generalized nonexpansive mappings in the setting of uniformly convex Banach spaces.

We next recall some useful definitions and basic concepts for this article.

Let M be a nonempty subset of a Banach space X and F : M M . We denote by Fix ( F ) the fixed-point set of F , that is, Fix ( F ) = { x M : F x = x } . A mapping F : M M is said to be a contraction if there exists k ( 0 , 1 ) such that for all r , s M , F r F s k r s . If k = 1 , then F is called nonexpansive and quasi nonexpansive if for all r M and p Fix ( F ) , F r p r p . A mapping F is said to be generalized nonexpansive if for all r , s X ,

1 / 2 r F r r s F r F s r s .

Definition 1

(See, e.g., [14]) A Banach space X is called uniformly convex if for each ε ( 0 , 2 ] there exists δ > 0 such that for r , s X with r 1 and s 1 , r s > ε implies r + s 2 δ .

Definition 2

(See, e.g., [14]) A mapping F : M M is said to satisfy condition (C) if for all ξ , η M , we have

1 / 2 ξ F ξ ξ η F ξ F η ξ η .

Indeed, this notion of Suzuki [14] was improved in [15].

Definition 3

[16] A Banach space X is said to satisfy Opial’s property [2] if for each sequence { ξ n } in X converging weakly to ξ X , we have

limsup n ξ n ξ < limsup n ξ n η

for all η X such that η ξ .

Lemma 1

(See, e.g., [[1], Proposition 3]). Let M be a nonempty subset of a Banach space X and F : M M . Suppose that X satisfies Opial’s property. Assume that F is a Suzuki generalized nonexpansive mapping. If { ξ n } converges weakly to t and lim n F ξ n ξ n = 0 , then F ( t ) = t , that is, I F is demiclosed at zero.

Lemma 2

([1], Theorem 5). Let M be a weakly compact convex subset of a uniformly convex Banach space X . Let F : M M . Assume that F is a Suzuki generalized nonexpansive mapping. Then F has a fixed point.

Definition 4

[17] Let { r n } n = 0 and { s n } n = 0 be two sequences that converge to the same fixed point p and r n p a n , and s n p b n for all n 0 . If the sequence { a n } n = 0 and { b n } n = 0 converge to a and b , respectively, and lim n a n a b n b = 0 , then we say that { r n } n = 0 converges to p faster than { s n } n = 0 .

Definition 5

[18] Let { u n } n = 0 be a sequence in M . Then an iteration procedure r n + 1 = f ( F , r n ) converging to a fixed point p is said to be F -stable or stable with respect to F , if for ε n = t n + 1 f ( F : u n ) , n N , we have lim n ε n = 0 if and only if lim n u n = p .

Lemma 3

[19] Let { r n } n = 0 and { t n } n = 0 be nonnegative real sequences satisfying the relation r n + 1 ( 1 t n ) r n + t n , where t n ( 0 , 1 ) for all n N , Σ n = 0 t n = and r n t n 0 as n . Then lim n r n = 0 .

Lemma 4

[20] Suppose that X is a uniformly convex Banach space and let { u n } be real sequence such that 0 < p u n q < 1 for all n 1 . Let { r n } and { s n } be sequences in X such that limsup n r n r , limsup n s n r , and limsup n u n r n + ( 1 u n ) s n ) = r hold for some r 0. Then lim n r n s n = 0 .

Proposition 1

(See, e.g., [14]) Let M be a nonempty subset of a Banach space X and F : M M be a mapping. Then

  1. If F is nonexpansive, then F is a Suzuki generalized nonexpansive mapping.

  2. If F is a Suzuki generalized nonexpansive mapping and has a fixed point, then F is a quasi nonexpansive mapping.

Also, the author in [14] proved the following lemma (see Lemma 7 in [14]).

Lemma 5

[14] Let M be a nonempty subset of a Banach space X and F : M M be a Suzuki generalized nonexpansive mapping. Then, for all r , s X , we have

F r F s 3 F r r + r s .

Let M be a nonempty closed convex subset of a Banach space X , and let { r n } be a bounded sequence in X . For s X , we set

r ( s , { r n } ) = limsup n r n s .

The asymptotic radius of { r n } relative to M is given by

r ( M , { r n } ) = inf { r ( s , { r n } ) : s M } ,

and the asymptotic center of { r n } relative to M is the set

A ( M , { r n } ) = { s M : r ( s , { r n } ) } = r ( M , { r n } ) .

It is known that, in a uniformly convex Banach space, A ( M , { ξ n } ) consists of exactly one point.

Next we discuss the existing iterative process.

Throughout this section, we suppose that { θ n } n = 0 , { η n } n = 0 and { ϑ n } n = 0 are real sequences in [ 0 , 1 ] and C is a nonempty subset of Banach space X .

In 2016, the authors in [21] introduced a new iteration process as follows:

(1) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = F ( ( 1 θ n ) F r n + θ n F t n ) , r n + 1 = F s n .

Subsequently, the authors in [22] introduced a new iteration process as follows:

(2) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = ( 1 θ n ) t n + θ n F t n , r n + 1 = ( 1 η n ) F t n + η n F s n .

In 2017, the authors in [4] introduced the following iteration process known as M * -iteration process:

(3) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = F ( ( 1 θ n ) r n + θ n F t n ) , r n + 1 = F s n .

Recently, in 2018, the authors in [3] introduced the following iteration process called K -iteration process and proved weak and strong convergence theorems for fixed points of Suzuki generalized nonexpansive mappings in the setting of uniformly convex Banach spaces.

(4) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = F ( ( 1 θ n ) F r n + θ n F t n ) , r n + 1 = F s n .

They have demonstrated that the K -iteration process converges faster than the S -iteration process, Picard- S iteration process, M -iteration process, and M -iteration process. In 2018, the author in [5] introduced the K iteration process and showed that K iteration process converges faster than Picard- S iteration process and S -iteration process.

(5) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = F ( ( 1 θ n ) t n + θ n F t n ) , r n + 1 = F s n .

In the same year, the authors in [6] introduced M -iteration process as follows:

(6) r 0 C , t n = ( 1 ϑ n ) r n + ϑ n F r n , s n = F t n , r n + 1 = F s n .

Recently, in 2019, the authors in [7] introduced the new iteration process called J -iteration process as follows:

(7) r 0 C , t n = F ( ( 1 ϑ n ) r n + ϑ n F r n ) , s n = F ( ( 1 θ n ) t n + θ n F t n ) , r n + 1 = F s n .

By numerical examples, it was demonstrated that J -iteration process converges faster than some known iteration processes. They also discussed the stability of the proposed iteration and proved fixed-point results in the context of the uniformly convex Banach spaces for Suzuki generalized nonexpansive mappings. In 2021, the authors in [8] introduced a new iteration process, namely, D -iteration process as follows:

(8) ξ 0 C ω n = F ( ( 1 ϑ n ) ξ n + ϑ n F ξ n ) η n = F ( ( 1 θ n ) F ξ n + θ n F ω n ) ξ n + 1 = F η n .

They proved that their iteration process (9) has a better convergence rate than (1), (4), (5), and (7). Furthermore, in [9], they proved that their D -iteration process is stable. Also they have proved the data dependency result and the error estimation for D -iteration process.

2 Main results

In this section, we present a new iteration process and analytically prove that it converges strongly to unique fixed point as well as stable and also prove that has better convergence rate than the existing iteration process.

First, we introduce a new iteration process called D -plus iteration process. It is defined as follows:

(9) r 0 C , t n = F ( ( 1 ϑ n ) r n + ϑ n F r n ) , s n = F ( ( 1 θ n ) t n + θ n F t n ) , r n + 1 = F ( ( 1 η n ) F t n + η n F s n ) .

We prove that D -plus iteration process converges faster than some existing iteration processes. We give some numerical experiments to show that the proposed iteration process has a better convergence rate than S -iteration process and Picard- S iteration process. It is shown that our iteration process is free from the selection of initial value. Its stability is also established under mild conditions.

In this section, we also generalized the strong convergence theorem “Theorem 2.1” for our iteration process, which shows that our iteration process strongly converge to unique fixed point. We also generalized some comparison result to represent that our iteration process is the fast convergent one.

Theorem 2.1

Let C be a nonempty closed convex subset of a Banach space X and F : C C be a contraction mapping. Let { r n } n = 0 be a sequence generated by D -plus iteration process with real sequences { θ n } n = 0 and { ϑ n } n = 0 in [0 1] satisfying Σ n = 0 ϑ n = or Σ n = 0 θ n = . Then { r n } n = 0 converges strongly to a unique fixed point of F .

Proof

Since F is a contraction in a Banach space, and F has a unique fixed point in C . Let us suppose that p is a fixed point of F . So we obtain

t n p = F ( ( 1 ϑ n ) r n + ϑ n F r n ) F p k ( 1 ϑ n ) r n + ϑ n F r n p k ( 1 ϑ n ) ( r n p ) + ϑ n ( F r n p ) k ( 1 ϑ n ) ( r n p ) + ϑ n F r n p k { ( 1 ϑ n ) r n p + k ϑ n r n p } = k { 1 ϑ n ( 1 k ) } r n p .

Also we have

s n p = F ( ( 1 θ n ) t n + θ n F t n ) F p k ( 1 θ n ) t n + θ n F t n p k ( 1 θ n ) ( t n p ) + θ n ( F t n p ) k ( 1 θ n ) t n p + θ n F t n p k { ( 1 θ n ) t n p + k θ n t n p } = k t n p k 2 { 1 ϑ n ( 1 k ) } r n p .

It follows that

r n + 1 p = F ( ( 1 η n ) F t n + η n F s n ) F p k [ ( 1 η n ) F t n p + η n F s n p ] k [ ( 1 η n ) k t n p + η n k s n p ] k 2 [ ( 1 η n ) t n p + η n s n p ] k 2 [ ( 1 η n ) t n p + k η n t n p ] = k 2 { 1 η n ( 1 k ) } t n p k 2 { 1 η n ( 1 k ) } { k { 1 ϑ n ( 1 k ) } r n p } = k 3 { 1 η n ( 1 k ) } { 1 ϑ n ( 1 k ) } r n p .

By repeating the aforementioned process, we obtain

r n p k 3 { 1 η n 1 ( 1 k ) } { 1 ϑ n 1 ( 1 k ) } r n 1 p r n 1 p k 3 { 1 η n 2 ( 1 k ) } { 1 ϑ n 2 ( 1 k ) } r n 2 p r n 2 p k 3 { 1 η n 3 ( 1 k ) } { 1 ϑ n 3 ( 1 k ) } r n 3 p r 1 p k 3 { 1 η 0 ( 1 k ) } { 1 ϑ 0 ( 1 k ) } r 0 p .

Therefore, we obtain

r n + 1 p k 3 ( n + 1 ) r 0 p i = 0 n { 1 η i ( 1 k ) } { 1 ϑ i ( 1 k ) } .

Since ( 1 k ) > 0 and ϑ n 1 for all n N . Therefore, we obtain 1 ϑ n ( 1 k ) < 1 and 1 η n ( 1 k ) < 1 for all n N . We know that 1 r e r for all r [ 0 , 1 ] . So we have

r n + 1 p k 3 ( n + 1 ) r 0 p e ( 1 k ) i = 0 n ϑ i i = 0 n ϑ i .

Thus, taking the limits n both sides, we obtain lim n r n p = 0 .□

Remark 1

From Theorem 2.1, by replacing the condition Σ n = 0 ϑ n = by Σ n = 0 θ n = and putting Σ n = 0 η n = 0 , then t n p k r n p and we obtain s n p k 2 { 1 θ n ( 1 k ) } r n p . Thus

r n + 1 p k 3 ( n + 1 ) r 0 p i = 0 n { 1 θ i ( 1 k ) } .

Therefore, we obtain the desired result.

Theorem 2.2

Let M be a nonempty closed convex subset of a Banach space X and F : M M be a contraction with a fixed point p . For a given r 0 = u 0 , let { r n } n = 0 and { u n } n = 0 be a sequence generated by D -plus iteration process and K -iteration process as in [5], respectively, with real sequences { θ n } n = 0 , { ϑ n } n = 0 and { η n } n = 0 in [ 0 , 1 ] satisfying ϑ ϑ n < 1 for some θ , ϑ > 0 and for all n N . Then { r n } n = 0 converges to p faster than { u n } n = 0 .

Proof

From inequality (10) of Theorem 3.2 in [5], we have

u n + 1 p k 2 ( n + 1 ) u 0 p i = 0 n { 1 θ i ( 1 k ) } .

Since θ θ n and for all n N , we obtain

u n + 1 p k 2 ( n + 1 ) u 0 p { 1 θ i ( 1 k ) } n + 1 .

Also, from Remark 1, we obtain

r n + 1 p k 3 ( n + 1 ) r 0 p i = 0 n { 1 θ i ( 1 k ) } .

Moreover, θ θ n for all n N gives

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

So we have

a n = k 2 ( n + 1 ) u 0 p { 1 θ i ( 1 k ) } n + 1

and

b n = k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Then

b n a n = k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 k 2 ( n + 1 ) u 0 p { 1 θ i ( 1 k ) } = k n + 1 .

Thus, we obtain lim n b n a n = 0 . Hence, the result follows.□

Now we prove that D -plus converges faster than K -iteration process [3].

Theorem 2.3

Let M be a nonempty closed convex subset of a Banach space X and F : M M be a contraction with a fixed point p . For a given r 0 = u 0 , let { r n } n = 0 and { u n } n = 0 be a sequence generated by D -plus iteration process and K -iteration process [3], respectively, with real sequences { θ n } n = 0 , { ϑ n } n = 0 and { η n } n = 0 in [ 0 , 1 ] satisfying ϑ ϑ n < 1 for some θ , ϑ > 0 and for all n N . Then { r n } n = 0 converges to p faster than { u n } n = 0 .

Proof

From Theorem 2.1, we have

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Since θ θ n and for all n N , we obtain

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Let a n = k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Now, from Theorem 3.2 in [3], we have

u n + 1 p k 3 ( n + 1 ) u 0 p i = 0 n { 1 ϑ θ i ( 1 k ) } .

Since ϑ ϑ n and for all n N , we obtain

u n + 1 p k 3 ( n + 1 ) u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 .

Here, we define

b n = k 3 ( n + 1 ) u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 .

Then

a n b n = k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 k 3 ( n + 1 ) ( u 0 p ) { 1 ϑ θ i ( 1 k ) } n + 1 = r 0 p { 1 θ i ( 1 k ) } n + 1 u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 .

Thus, taking limit as n , we have lim n a n b n = 0 . Hence, the result follows.□

Now we prove that D -plus converges faster than M -iteration process [6].

Theorem 2.4

Let M be a nonempty closed convex subset of a Banach space X and F : M M be a contraction with a fixed point p . For a given r 0 = u 0 , let { r n } n = 0 and { u n } n = 0 be sequences generated by D -plus iteration process and M -iteration process [6], respectively, with real sequences { θ n } n = 0 , { ϑ n } n = 0 and { η n } n = 0 in [ 0 , 1 ] satisfying ϑ ϑ n < 1 for some θ , ϑ > 0 and for all n N . Then { r n } n = 0 converges to p faster than { u n } n = 0 .

Proof

From Theorem 2.1, we have

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Since θ θ n and for all n N , we obtain

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

We note that M -iteration is defined by

(10) u 0 C , w n = ( 1 ϑ n ) u n + ϑ n F u n , v n = F w n , u n + 1 = F v n .

Then we have

w n p = ( ( 1 ϑ n ) u n + ϑ n F u n ) F p ( 1 ϑ n ) u n + ϑ n F u n p ( 1 ϑ n ) ( u n p ) + ϑ n ( F u n p ) ( 1 ϑ n ) u n p + ϑ n F u n p ( 1 ϑ n ) u n p + k ϑ n u n p = k { 1 ϑ n ( 1 k ) } u n p .

Now,

v n p F w n p k w n p k { 1 ϑ n ( 1 k ) } u n p .

Therefore, we obtain

u n + 1 p F v n p k v n p k 2 { 1 ϑ n ( 1 k ) } u n p .

By repeating the aforementioned process, we obtain

u n p k 2 { 1 ϑ n 1 ( 1 k ) } u n 1 p u n 1 p k 2 { 1 ϑ n 2 ( 1 k ) } u n 2 p u n 2 p k 2 { 1 ϑ n 3 ( 1 k ) } u n 3 p u 1 p k 2 { 1 ϑ 0 ( 1 k ) } u 0 p .

Therefore, we obtain u n + 1 p k 2 ( n + 1 ) u 0 p i = 0 n { 1 ϑ i ( 1 k ) } .

Now, since ϑ ϑ n and for all n N , we obtain

u n + 1 p k 2 ( n + 1 ) u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 .

Let b n = k 2 ( n + 1 ) u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 . Then, we have

a n b n = r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 k 2 ( n + 1 ) u 0 p { 1 ϑ θ i ( 1 k ) } n + 1 .

Thus, taking limit as n , we obtain lim n a n b n = 0 . Hence, the result follows.□

Next, we prove that D -plus converges faster than that of the M -iteration process [4]. Here, we consider the rate of convergence of M -iteration process under contraction and compare it with the D -plus iteration process.

Theorem 2.5

Let M be a nonempty closed convex subset of a Banach space X and F : M M be a contraction with a fixed point p . For a given r 0 = u 0 , let { r n } n = 0 and { u n } n = 0 be sequences generated by D -plus iteration process and M -iteration process [4], respectively, with real sequences { θ n } n = 0 , { ϑ n } n = 0 and { η n } n = 0 in [ 0 , 1 ] satisfying ϑ ϑ n < 1 for some θ , ϑ > 0 and for all n N . Then { r n } n = 0 converges to p faster than { u n } n = 0 .

Proof

From Theorem 2.1, we have

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Since θ θ n and for all n N , we obtain

r n + 1 p k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

We define

a n = k 3 ( n + 1 ) r 0 p { 1 θ i ( 1 k ) } n + 1 .

Note that M -iteration is defined by

(11) u 0 C , w n = ( 1 ϑ n ) u n + ϑ n F u n , v n = F ( ( 1 θ n ) u n + θ n F w n ) , u n + 1 = F v n .

Then we have

w n p = ( ( 1 ϑ n ) u n + ϑ n F u n ) F p ( 1 ϑ n ) u n + ϑ n F u n p ( 1 ϑ n ) ( u n p ) + ϑ n ( F u n p ) ( 1 ϑ n ) u n p + ϑ n F u n p ( 1 ϑ n ) u n p + k ϑ n u n p = { 1 ϑ n ( 1 k ) } u n p .

Now

v n p = F ( ( 1 θ n ) u n + θ n F w n ) F p k ( 1 θ n ) u n + θ n F w n p k ( 1 θ n ) ( u n p ) + θ n ( F w n p ) k ( 1 θ n ) u n p + θ n F w n p k { ( 1 θ n ) u n p + k θ n w n p } k { ( 1 θ n ) u n p + k θ n { 1 ϑ n ( 1 k ) } u n p } = k { ( 1 θ n ) + k θ n k θ n ϑ n ( 1 k ) } u n p = k { 1 ( 1 k ) θ n k θ n ϑ n ( 1 k ) } u n p = k { 1 θ n ( 1 k ) ( 1 k ϑ n ) } u n p .

It follows that

u n + 1 p F v n p k 2 { 1 θ n ( 1 k ) ( 1 k ϑ n ) } u n p .

By repeating the aforementioned process, we obtain

u n p k 2 { 1 θ n 1 ( 1 k ) ( 1 k ϑ n 1 ) } u n 1 p u n 1 p k 2 { 1 θ n 2 ( 1 k ) ( 1 k ϑ n 2 ) } u n 2 p u n 2 p k 2 { 1 θ n 3 ( 1 k ) ( 1 k ϑ n 3 ) } u n 3 p u 1 p k 2 { 1 θ 0 ( 1 k ) ( 1 k ϑ 0 ) } u 0 p .

Therefore, we obtain

u n + 1 p k 2 ( n + 1 ) u 0 p i = 0 n { 1 θ i ( 1 k ) ( 1 k ϑ i ) } .

Now, since θ θ n ϑ ϑ n and for all n N , we obtain

u n + 1 p k 2 ( n + 1 ) ( u 0 p ) { 1 θ i ( 1 k ) ( 1 k ϑ i ) } n + 1 .

Let b n = k 2 ( n + 1 ) ( u 0 p ) { 1 θ i ( 1 k ) ( 1 k ϑ i ) } n + 1 . Then

a n b n = k 3 ( n + 1 ) ( r 0 p ) { 1 θ i ( 1 k ) } n + 1 k 2 ( n + 1 ) ( u 0 p ) { 1 θ i ( 1 k ) ( 1 k ϑ i ) } n + 1 = k n + 1 { 1 θ i ( 1 k ) } n + 1 { 1 θ i ( 1 k ) ( 1 k ϑ i ) } n + 1 .

Thus, taking limit as n , we obtain lim n a n b n = 0 . Hence, the result follows.□

Next we prove that our new iteration D -plus is stable.

Theorem 2.6

Let M be a nonempty closed convex subset of a Banach space X and F : M M be a contraction. Let { r n } n = 0 be a sequence generated by D-plus iteration process, with real sequences { θ n } n = 0 , { ϑ n } n = 0 and { η n } n = 0 in [ 0 , 1 ] satisfying n = 0 ϑ n = . Then D -plus iterative process is stable.

Proof

Let { r n } n = 0 be a sequence in C . Suppose that the sequence generated by D -plus iteration process is defined by r n + 1 = f ( F ; r n ) converging to unique fixed point p (follows from Theorem 2.1). Set

ε n = r n + 1 f ( F ; r n ) .

We will prove that lim n ε n = 0 if and only if lim n r n = p .

Let lim n ε n = 0 . Then, we have

r n + 1 p r n + 1 f ( F , r n ) + f ( F , r n ) p = ε n + r n + 1 p .

From Theorem 2.1, we obtain

r n + 1 p k 3 { 1 η n ( 1 k ) } { 1 ϑ n ( 1 k ) } r n p .

Since 0 < k < 1 , 0 η n 1 , and 0 ϑ n 1 for all n N and lim n ε n = 0 , and by using Lemma 3, we obtain lim n r n p = 0 . Hence, lim n r n = p .

Conversely, let lim n r n = p . Then we have

ε n = r n + 1 f ( F , r n ) r n + 1 p + f ( F , r n ) p , r n + 1 p + k 3 { 1 η n ( 1 k ) } { 1 ϑ n ( 1 k ) } x n p .

Therefore, we have lim n ε n = 0 . Hence, D -plus iteration process is stable.□

Remark 2

As after reading literature, there raise a question, is it possible to develop an iteration process that has better convergence rate? The main objective of this article is to present an iterative process that has better convergence rate and stable. To fulfil this aim, we attain the aforementioned mention result (Theorems 2.12.6).

Theorem 2.1 is the main result, which shows that our iterative process strongly converges to unique fixed point. Theorems 2.22.5 show the analytic comparison of our iteration process with existing iterative process. The last one result represents that our iteration process is stable.

In next section, we present weak and strong convergence result in the setting of uniformly convex Banach spaces.

3 Convergence analysis

Lemma 6

Let M be a nonempty closed convex subset of a Banach space X, and let F : M M be a mapping satisfying condition (C) with Fix ( F ) . For arbitrary chosen r 0 M , let the sequence { r n } be generated by D-plus iteration process. Then lim n r n p exists for any p Fix ( F ) .

Proof

Let p Fix ( F ) and t C . Since F satisfies condition (C), it follows that 1 / 2 p F t = 0 p t implies F p F t p t . So by Proposition 1 (ii), we have

t n p = ( 1 ϑ n ) r n + ϑ n F r n p ( 1 ϑ n ) r n p + ϑ n F r n p ( 1 ϑ n ) r n p + ϑ n r n p = r n p .

It follows that

s n p = F ( ( 1 θ n ) t n + θ n F t n ) p ( 1 θ n ) F t n + θ n F t n p ( 1 θ n ) F t n p + θ n F t n p ( 1 θ n ) t n p + θ n t n p = t n p r n p .

Then

r n + 1 p = F ( ( 1 η n ) F t n + η n F s n ) F p ( 1 η n ) ( F t n p ) + η n ( F s n p ) [ ( 1 η n ) F t n p + η n F s n p ] ( 1 η n ) t n p + η n s n p ( 1 η n ) r n p + η n r n p = r n p .

This implies that { r n p } is bounded and nonincreasing for all p Fix ( F ) . Hence, lim n r n p exists as required.□

Theorem 3.1

Let M be a nonempty closed convex subset of uniformly convex Banach space X , and let F : M M be a mapping satisfying condition (C). For arbitrary chosen r 0 M , let the sequence { r n } be generated by D -plus iteration process for all n 1 where { θ n } and { ϑ n } are real sequences in [ a , b ] for some a , b with 0 < a b < 1 . Then Fix ( F ) if and only if { r n } is bounded and lim n F r n r n = 0 .

Proof

Suppose Fix ( F ) and p Fix ( F ) . Then, by Lemma 6, we have lim n r n p exists and { r n } is bounded. Let lim n r n p = r . Then, by Lemma 6, we have

limsup n t n p limsup n r n p = r .

By Proposition 1 (ii), we obtain

limsup n T r n p limsup n r n p = r .

On the other hand, we see that

r n + 1 p = F ( ( 1 η n ) F t n + η n F s n ) p = F ( ( 1 η n ) F t n + η n F s n ) F p ( 1 η n ) ( F t n p ) + η n ( F s n p ) [ ( 1 η n ) F t n p + η n F s n p ] ( 1 η n ) t n p + η n s n p ( 1 η n ) r n p + η n r n p = r n p .

Therefore, r liminf n t n p . Thus, we obtain

r = lim n t n p = lim n ( 1 ϑ n ) r n + ϑ n F r n p = lim n ϑ n ( F r n p ) + ( 1 ϑ n ) ( r n p ) .

Then, by using aforementioned inequalities and Lemma 4, we have

lim n F r n r n = 0 .

Conversely, suppose that { r n } is bounded and lim n F r n r n = 0 . Let p A ( M , { r n } ) . By Lemma 4, we have

r ( F p , { r n } ) = limsup n r n F p limsup n ( 3 F r n r n + r n p ) limsup n r n p = r ( p , { r n } ) .

This implies that F p A ( C , { r n } ) . Since X is uniformly convex, A ( C , { r n } ) is singleton, and hence, we have F p = p . Hence, Fix ( F ) .

Next, we prove strong and weak convergence results of sequences generated by D -plus iteration process for Suzuki generalized nonexpansive mappings in the setting of uniformly convex Banach spaces.□

Theorem 3.2

Let M be a nonempty closed convex subset of a uniformly Banach space X , and let F : M M be a mapping satisfying condition (C), where { θ n } and { ϑ n } are real sequences in [ a , b ] for some a , b with 0 < a b < 1 . Such that Fix ( F ) . Let X satisfy the Opial’s property. For arbitrary chosen r 0 M , let the sequence { r n } be generated by D -plus iteration process for all n 1 . Then { r n } converges weakly to p Fix ( F ) .

Proof

Since Fix ( F ) , so by Theorem 3.1, we have { r n } is bounded. So lim n F r n r n = 0 . Since X is uniformly convex hence reflexive, so by Eberlin’s theorem, there exists a subsequence { r n j } of { r n } , which converges weakly to some p 1 X . Since M is closed and convex, by Mazur’s theorem, p 1 C . By Lemma 2, we have p 1 Fix ( F ) .

Now, we show that { r n } converges weakly to p 1 . In fact, if this is not true, so there must exists a subsequence { r n k } for { r n } such that { ξ n k } converges weakly to p 2 C and p 2 p 1 . By Lemma 2, p 2 Fix ( F ) . Since lim n r n p exists for all p Fix ( F ) . By Theorem 3.1 and Opial’s property, we have

lim n r n p 1 = lim j r n j p 1 < lim j r n j p 2 = lim n r n p 2 = lim k r n k p 2 < lim k r n k p 1 = lim n r n p 1 ,

which is contradiction. So p 1 = p 2 . This implies that { r n } converges weakly to a fixed point of F .□

Theorem 3.3

Let M be a nonempty closed convex subset of a uniformly Banach space X , and let F : M M be a mapping satisfying condition (C) where { θ n } and { ϑ n } are real sequences in [ a , b ] for some a , b with 0 < a b < 1 . Suppose that Fix ( F ) . Let C be a nonempty convex subset of X . Then { r n } converges strongly to p Fix ( F ) .

Proof

By Lemma 2, we have Fix ( F ) , and so, by Theorem 3.1, we obtain lim n F r n r n = 0 . Since M is compact, there exists a subsequence { r n j } of { r n } , which converges strongly to p for some p C . By Lemma 5, we have

r n k F p 3 F r n k r n k + r n k p , for all n 1 .

Letting k , we obtain p Fix ( F ) . By Lemma 6, lim n r n p exists for every p Fix ( F ) . So { r n } converges strongly to p .□

4 Numerical examples

In this section, we present a numerical example to support our analytic result of Section 2. First, we take a contraction map and calculate fixed point for it by using different iteration process. Graphically as well as with the help of table, we compare the calculation of our iteration process with the existing iteration process. Both “table and graphs” show the efficiency of our iteration process. As some of the iteration process of literature fails to converge at particular initial value. Their convergence depends on the selection of initial value. The objective of this article is to present the fastest convergent iterative method as well as its convergent independent from the selection of the initial value. In Example 2, we take different initial value for a contraction map in Example 1. Figures 1, 2, 3, and 4 show that either the initial value is above or below the fixed point, convergence of our iteration process does not effect.

Figure 1 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus iteration process when initial guess is 20.5.
Figure 1

Convergence of D -plus iteration process when initial guess is 20.5.

Figure 2 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus iteration process when initial guess is 10.5.
Figure 2

Convergence of D -plus iteration process when initial guess is 10.5.

Figure 3 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus iteration process when initial guess is 0.5.
Figure 3

Convergence of D -plus iteration process when initial guess is 0.5.

Figure 4 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus iteration process when initial guess is 
                     
                        
                        
                           −
                           5.5
                        
                        -5.5
                     
                  .
Figure 4

Convergence of D -plus iteration process when initial guess is 5.5 .

Example 1

Let us define a function F : R R by F ( r ) = ( r 2 8 r + 40 ) 1 2 . Then clearly F is a contraction. Let θ n = 2 n 3 n + 1 , ϑ n = 3 n 4 n + 5 , and η n = 4 n 5 n + 1 . The initial value r 0 = 40.5 is given in Table 1. Figure 5 shows the convergence of iteration processes. The efficiency of D -plus iteration process is shown.

Table 1 presents that our iteration process is most efficient and fastest compared to the exiting iterative process of literature. We also represent efficiency of our iteration process graphically.

Table 1

Convergence of D -plus, Picard- S , and S iteration processes in Example 1

D -plus Picard- S S
r 0 40.5 40.5 40.5
r 1 29.599069 33.190836 36.827299
r 2 16.743028 25.484353 32.591647
r 3 6.5593682 17.820134 28.059416
r 4 5.0075393 10.863721 23.430599
r 5 5.0000166 6.1638489 18.843365
r 6 5 5.0537052 14.448288
r 7 5 5.0014824 10.481527
r 8 5 5.0000392 7.3683714
r 9 5 5.0000010 5.6315028
r 10 5 5.0000001 5.1036913

From Figures 5, 6, and Table 1, we can easily see that D -plus iteration process has a better convergence behavior than Picard- S and S -iteration processes.

Figure 5 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus, Picard-
                     
                        
                        
                           S
                        
                        S
                     
                   and 
                     
                        
                        
                           S
                        
                        S
                     
                  -iteration processes in Example 1.
Figure 5

Convergence of D -plus, Picard- S and S -iteration processes in Example 1.

Figure 6 
               Convergence of 
                     
                        
                        
                           D
                        
                        D
                     
                  -plus, Picard-
                     
                        
                        
                           S
                        
                        S
                     
                   and 
                     
                        
                        
                           S
                        
                        S
                     
                  -iteration processes in Example 1.
Figure 6

Convergence of D -plus, Picard- S and S -iteration processes in Example 1.

Hence, in Example 1, computationally as well as graphically, it is clear that D iteration process is more efficient then existing iterative process.

In the following example, we present graphical representation for different initial values of our iteration process.

Example 2

Let us define a function F as in Example 1. Let r 0 = 20.5 , r 0 = 10.5 , r 0 = 0.5 , and r 0 = 5.5 be different initial values in D -plus iteration process in Figures 14, respectively.

On account of Figures 14, we can easily see that D -plus iteration process is independent from the selection of initial values.

5 Conclusion

In this article, we present a new instantly convergent iterative method to approximate fixed points of contractions. First, we have presented D -plus iteration process and then proved its convergence to a unique fixed point and its stability. Also, analytically and numerically showed that the proposed iteration process has a better convergence rate than some existing iteration processes defined in [38,15,2123]. Furthermore, it was shown that the convergence of D -plus iteration process is independent from the choice of initial values.


;

Acknowledgements

The authors thank to their universities.

  1. Funding information: We declare that funding is applicable for our paper.

  2. Author contributions: All authors contributed equally and significantly in writing this article. All authors have read and agreed to the published version of the manuscript.

  3. Conflict of interest: The authors declare that they have no competing interest.

  4. Data availability statement: Not applicable.

References

[1] W. R. Mann, Mean value methods in iteration, Proc. Am. Math. Soc. 4 (1953), 506–510. 10.1090/S0002-9939-1953-0054846-3Search in Google Scholar

[2] S. Ishikawa, Fixed points by a new iteration method, Proc. Am. Math. Soc. 44 (1974), 147–150. 10.1090/S0002-9939-1974-0336469-5Search in Google Scholar

[3] N. Hussain, K. Ullah, and M. Arshad, Fixed point approximation for Suzuki generalized nonexpansive mappings via new iteration process, Nonlinear Convex Anal. 19 (2018), 1383–1393. Search in Google Scholar

[4] K. Ullah and M. Arshad, New iteration process and numerical reckoning fixed points in Banach, U.P.B. Sci. Bull. Ser. A 79 (2017), 113–122. Search in Google Scholar

[5] K. Ullah and M. Arshad, New three-step iteration process and fixed point approximation in Banach spaces, J. Linear. Topol. Algebra 7 (2018), 87–100. Search in Google Scholar

[6] K. Ullah and M. Arshad, Numerical reckoning fixed points for Suzukias generalized nonexpansive mappings via new iteration process, Filomat 32 (2018), 187–196. 10.2298/FIL1801187USearch in Google Scholar

[7] J. D. Bhutia and K. Tiwary, New iteration process for approximating fixed points in Banach spaces, J. Linear. Topol. Algebra 8 (2019), 237–250. Search in Google Scholar

[8] A. Hussain, N. Hussain, and D. Ali, Estimation of newly established iterative scheme for genralized and nonexpansive mapping, J. Function Spaces 2021 (2021), 1–9. 10.1155/2021/6675979Search in Google Scholar

[9] A. Hussain, D. Ali, and E. Karapinar, Stability data dependency and errors eestimation for genral iteration method, Alexandra Eng. J. 60 (2021), 703–710. 10.1016/j.aej.2020.10.002Search in Google Scholar

[10] R. P. Agarwal, D. O’Regan, and D. R. Sahu, Iterative construction of fixed points of nearly asymptotically nonexpansive mappings, J. Nonlinear Convex Anal. 8 (2007), 61–79. Search in Google Scholar

[11] M. A. Noor, New approximation schemes for general variational inequalities, J. Math. Anal. Appl. 251 (2000), 217–229. 10.1006/jmaa.2000.7042Search in Google Scholar

[12] M. Abbas and T. Nazir, A new faster iteration process applied to constrained minimization and feasibilty problems, Mat. Vesn. 66 (2014), 223–234. Search in Google Scholar

[13] K. Ullah, K. Iqbal, and M. Arshad, Some convergence results using K iteration process in CAT(0) spaces, Fixed Point Theory Appl. 2018 (2018), 11. 10.1186/s13663-018-0637-0Search in Google Scholar

[14] T. Suzuki, Fixed point theorems and convergence theorems for some genralized nonexpansive mappings, J. Math. Anal. Appl. 340 (2008), 1088–1095. 10.1016/j.jmaa.2007.09.023Search in Google Scholar

[15] E. Karapinar and K. Tas, Generalized (C)-conditions and related fixed point theorems, Comput. Math. Appl. 61 (2011), no. 11, 3370–3380. 10.1016/j.camwa.2011.04.035Search in Google Scholar

[16] Z. Opial, Weak convergence of the sequence of successive approximations for nonexpensaive mappings, Bull. Am. Math. Soc. 73 (1967), 595–597. 10.1090/S0002-9904-1967-11761-0Search in Google Scholar

[17] V. Berinde, Iterative Approximation of Fixed Points, Springer, Berlin, 2007. 10.1109/SYNASC.2007.49Search in Google Scholar

[18] A. M. Harder, Fixed Point Theory and Stability Results for Fixed Point Iteration Procedures, Ph.D Thesis, University of Missouri-Rolla, Missouri, 1987. Search in Google Scholar

[19] X. Weng, Fixed point iteration for local strictly pseudocontractive mapping, Proc. Am. Math. Soc. 113 (1991), 727–731. 10.1090/S0002-9939-1991-1086345-8Search in Google Scholar

[20] J. Schu, Weak and strong convergence to fixed points of asymptotically nonexpansive mappings, Bull. Aust. Math. Soc. 43 (1991), 153–159. 10.1017/S0004972700028884Search in Google Scholar

[21] B. S. Thakur, D. Thakur, and M. Postolache, A new iterative scheme for numerical reckoning fixed points of Suzukias generalized nonexpansive mappings, Appl. Math. Comp. 275 (2016), 147–155. 10.1016/j.amc.2015.11.065Search in Google Scholar

[22] B. S. Thakur, D. Thakur, and M. Postolache, A new iteration scheme for approximating fixed points of nonexpansive mappings, Filomat 30 (2016), 2711–2720. 10.2298/FIL1610711TSearch in Google Scholar

[23] K. Goebel and W. A. Kirk, Topic in Metric Fixed Point Theory, Cambridge Universty Press, Cambridge, UK, 1990. 10.1017/CBO9780511526152Search in Google Scholar

Received: 2021-05-28
Revised: 2022-03-25
Accepted: 2022-04-14
Published Online: 2022-12-31

© 2022 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. A random von Neumann theorem for uniformly distributed sequences of partitions
  3. Note on structural properties of graphs
  4. Mean-field formulation for mean-variance asset-liability management with cash flow under an uncertain exit time
  5. The family of random attractors for nonautonomous stochastic higher-order Kirchhoff equations with variable coefficients
  6. The intersection graph of graded submodules of a graded module
  7. Isoperimetric and Brunn-Minkowski inequalities for the (p, q)-mixed geominimal surface areas
  8. On second-order fuzzy discrete population model
  9. On certain functional equation in prime rings
  10. General complex Lp projection bodies and complex Lp mixed projection bodies
  11. Some results on the total proper k-connection number
  12. The stability with general decay rate of hybrid stochastic fractional differential equations driven by Lévy noise with impulsive effects
  13. Well posedness of magnetohydrodynamic equations in 3D mixed-norm Lebesgue space
  14. Strong convergence of a self-adaptive inertial Tseng's extragradient method for pseudomonotone variational inequalities and fixed point problems
  15. Generic uniqueness of saddle point for two-person zero-sum differential games
  16. Relational representations of algebraic lattices and their applications
  17. Explicit construction of mock modular forms from weakly holomorphic Hecke eigenforms
  18. The equivalent condition of G-asymptotic tracking property and G-Lipschitz tracking property
  19. Arithmetic convolution sums derived from eta quotients related to divisors of 6
  20. Dynamical behaviors of a k-order fuzzy difference equation
  21. The transfer ideal under the action of orthogonal group in modular case
  22. The multinomial convolution sum of a generalized divisor function
  23. Extensions of Gronwall-Bellman type integral inequalities with two independent variables
  24. Unicity of meromorphic functions concerning differences and small functions
  25. Solutions to problems about potentially Ks,t-bigraphic pair
  26. Monotonicity of solutions for fractional p-equations with a gradient term
  27. Data smoothing with applications to edge detection
  28. An ℋ-tensor-based criteria for testing the positive definiteness of multivariate homogeneous forms
  29. Characterizations of *-antiderivable mappings on operator algebras
  30. Initial-boundary value problem of fifth-order Korteweg-de Vries equation posed on half line with nonlinear boundary values
  31. On a more accurate half-discrete Hilbert-type inequality involving hyperbolic functions
  32. On split twisted inner derivation triple systems with no restrictions on their 0-root spaces
  33. Geometry of conformal η-Ricci solitons and conformal η-Ricci almost solitons on paracontact geometry
  34. Bifurcation and chaos in a discrete predator-prey system of Leslie type with Michaelis-Menten prey harvesting
  35. A posteriori error estimates of characteristic mixed finite elements for convection-diffusion control problems
  36. Dynamical analysis of a Lotka Volterra commensalism model with additive Allee effect
  37. An efficient finite element method based on dimension reduction scheme for a fourth-order Steklov eigenvalue problem
  38. Connectivity with respect to α-discrete closure operators
  39. Khasminskii-type theorem for a class of stochastic functional differential equations
  40. On some new Hermite-Hadamard and Ostrowski type inequalities for s-convex functions in (p, q)-calculus with applications
  41. New properties for the Ramanujan R-function
  42. Shooting method in the application of boundary value problems for differential equations with sign-changing weight function
  43. Ground state solution for some new Kirchhoff-type equations with Hartree-type nonlinearities and critical or supercritical growth
  44. Existence and uniqueness of solutions for the stochastic Volterra-Levin equation with variable delays
  45. Ambrosetti-Prodi-type results for a class of difference equations with nonlinearities indefinite in sign
  46. Research of cooperation strategy of government-enterprise digital transformation based on differential game
  47. Malmquist-type theorems on some complex differential-difference equations
  48. Disjoint diskcyclicity of weighted shifts
  49. Construction of special soliton solutions to the stochastic Riccati equation
  50. Remarks on the generalized interpolative contractions and some fixed-point theorems with application
  51. Analysis of a deteriorating system with delayed repair and unreliable repair equipment
  52. On the critical fractional Schrödinger-Kirchhoff-Poisson equations with electromagnetic fields
  53. The exact solutions of generalized Davey-Stewartson equations with arbitrary power nonlinearities using the dynamical system and the first integral methods
  54. Regularity of models associated with Markov jump processes
  55. Multiplicity solutions for a class of p-Laplacian fractional differential equations via variational methods
  56. Minimal period problem for second-order Hamiltonian systems with asymptotically linear nonlinearities
  57. Convergence rate of the modified Levenberg-Marquardt method under Hölderian local error bound
  58. Non-binary quantum codes from constacyclic codes over 𝔽q[u1, u2,…,uk]/⟨ui3 = ui, uiuj = ujui
  59. On the general position number of two classes of graphs
  60. A posteriori regularization method for the two-dimensional inverse heat conduction problem
  61. Orbital stability and Zhukovskiǐ quasi-stability in impulsive dynamical systems
  62. Approximations related to the complete p-elliptic integrals
  63. A note on commutators of strongly singular Calderón-Zygmund operators
  64. Generalized Munn rings
  65. Double domination in maximal outerplanar graphs
  66. Existence and uniqueness of solutions to the norm minimum problem on digraphs
  67. On the p-integrable trajectories of the nonlinear control system described by the Urysohn-type integral equation
  68. Robust estimation for varying coefficient partially functional linear regression models based on exponential squared loss function
  69. Hessian equations of Krylov type on compact Hermitian manifolds
  70. Class fields generated by coordinates of elliptic curves
  71. The lattice of (2, 1)-congruences on a left restriction semigroup
  72. A numerical solution of problem for essentially loaded differential equations with an integro-multipoint condition
  73. On stochastic accelerated gradient with convergence rate
  74. Displacement structure of the DMP inverse
  75. Dependence of eigenvalues of Sturm-Liouville problems on time scales with eigenparameter-dependent boundary conditions
  76. Existence of positive solutions of discrete third-order three-point BVP with sign-changing Green's function
  77. Some new fixed point theorems for nonexpansive-type mappings in geodesic spaces
  78. Generalized 4-connectivity of hierarchical star networks
  79. Spectra and reticulation of semihoops
  80. Stein-Weiss inequality for local mixed radial-angular Morrey spaces
  81. Eigenvalues of transition weight matrix for a family of weighted networks
  82. A modified Tikhonov regularization for unknown source in space fractional diffusion equation
  83. Modular forms of half-integral weight on Γ0(4) with few nonvanishing coefficients modulo
  84. Some estimates for commutators of bilinear pseudo-differential operators
  85. Extension of isometries in real Hilbert spaces
  86. Existence of positive periodic solutions for first-order nonlinear differential equations with multiple time-varying delays
  87. B-Fredholm elements in primitive C*-algebras
  88. Unique solvability for an inverse problem of a nonlinear parabolic PDE with nonlocal integral overdetermination condition
  89. An algebraic semigroup method for discovering maximal frequent itemsets
  90. Class-preserving Coleman automorphisms of some classes of finite groups
  91. Exponential stability of traveling waves for a nonlocal dispersal SIR model with delay
  92. Existence and multiplicity of solutions for second-order Dirichlet problems with nonlinear impulses
  93. The transitivity of primary conjugacy in regular ω-semigroups
  94. Stability estimation of some Markov controlled processes
  95. On nonnil-coherent modules and nonnil-Noetherian modules
  96. N-Tuples of weighted noncommutative Orlicz space and some geometrical properties
  97. The dimension-free estimate for the truncated maximal operator
  98. A human error risk priority number calculation methodology using fuzzy and TOPSIS grey
  99. Compact mappings and s-mappings at subsets
  100. The structural properties of the Gompertz-two-parameter-Lindley distribution and associated inference
  101. A monotone iteration for a nonlinear Euler-Bernoulli beam equation with indefinite weight and Neumann boundary conditions
  102. Delta waves of the isentropic relativistic Euler system coupled with an advection equation for Chaplygin gas
  103. Multiplicity and minimality of periodic solutions to fourth-order super-quadratic difference systems
  104. On the reciprocal sum of the fourth power of Fibonacci numbers
  105. Averaging principle for two-time-scale stochastic differential equations with correlated noise
  106. Phragmén-Lindelöf alternative results and structural stability for Brinkman fluid in porous media in a semi-infinite cylinder
  107. Study on r-truncated degenerate Stirling numbers of the second kind
  108. On 7-valent symmetric graphs of order 2pq and 11-valent symmetric graphs of order 4pq
  109. Some new characterizations of finite p-nilpotent groups
  110. A Billingsley type theorem for Bowen topological entropy of nonautonomous dynamical systems
  111. F4 and PSp (8, ℂ)-Higgs pairs understood as fixed points of the moduli space of E6-Higgs bundles over a compact Riemann surface
  112. On modules related to McCoy modules
  113. On generalized extragradient implicit method for systems of variational inequalities with constraints of variational inclusion and fixed point problems
  114. Solvability for a nonlocal dispersal model governed by time and space integrals
  115. Finite groups whose maximal subgroups of even order are MSN-groups
  116. Symmetric results of a Hénon-type elliptic system with coupled linear part
  117. On the connection between Sp-almost periodic functions defined on time scales and ℝ
  118. On a class of Harada rings
  119. On regular subgroup functors of finite groups
  120. Fast iterative solutions of Riccati and Lyapunov equations
  121. Weak measure expansivity of C2 dynamics
  122. Admissible congruences on type B semigroups
  123. Generalized fractional Hermite-Hadamard type inclusions for co-ordinated convex interval-valued functions
  124. Inverse eigenvalue problems for rank one perturbations of the Sturm-Liouville operator
  125. Data transmission mechanism of vehicle networking based on fuzzy comprehensive evaluation
  126. Dual uniformities in function spaces over uniform continuity
  127. Review Article
  128. On Hahn-Banach theorem and some of its applications
  129. Rapid Communication
  130. Discussion of foundation of mathematics and quantum theory
  131. Special Issue on Boundary Value Problems and their Applications on Biosciences and Engineering (Part II)
  132. A study of minimax shrinkage estimators dominating the James-Stein estimator under the balanced loss function
  133. Representations by degenerate Daehee polynomials
  134. Multilevel MC method for weak approximation of stochastic differential equation with the exact coupling scheme
  135. Multiple periodic solutions for discrete boundary value problem involving the mean curvature operator
  136. Special Issue on Evolution Equations, Theory and Applications (Part II)
  137. Coupled measure of noncompactness and functional integral equations
  138. Existence results for neutral evolution equations with nonlocal conditions and delay via fractional operator
  139. Global weak solution of 3D-NSE with exponential damping
  140. Special Issue on Fractional Problems with Variable-Order or Variable Exponents (Part I)
  141. Ground state solutions of nonlinear Schrödinger equations involving the fractional p-Laplacian and potential wells
  142. A class of p1(x, ⋅) & p2(x, ⋅)-fractional Kirchhoff-type problem with variable s(x, ⋅)-order and without the Ambrosetti-Rabinowitz condition in ℝN
  143. Jensen-type inequalities for m-convex functions
  144. Special Issue on Problems, Methods and Applications of Nonlinear Analysis (Part III)
  145. The influence of the noise on the exact solutions of a Kuramoto-Sivashinsky equation
  146. Basic inequalities for statistical submanifolds in Golden-like statistical manifolds
  147. Global existence and blow up of the solution for nonlinear Klein-Gordon equation with variable coefficient nonlinear source term
  148. Hopf bifurcation and Turing instability in a diffusive predator-prey model with hunting cooperation
  149. Efficient fixed-point iteration for generalized nonexpansive mappings and its stability in Banach spaces
Downloaded on 8.12.2025 from https://www.degruyterbrill.com/document/doi/10.1515/math-2022-0461/html
Scroll to top button