Home A numerical solution of problem for essentially loaded differential equations with an integro-multipoint condition
Article Open Access

A numerical solution of problem for essentially loaded differential equations with an integro-multipoint condition

  • Zhazira M. Kadirbayeva EMAIL logo and Symbat S. Kabdrakhova EMAIL logo
Published/Copyright: October 12, 2022

Abstract

We study a linear boundary value problem for systems of essentially loaded differential equations with an integro-multipoint condition. We make use of the numerical implementation of the Dzhumabaev parametrization method to obtain the desired result, which is well supported by two numerical examples.

MSC 2010: 34B10; 45J05; 65L06

1 Introduction and problem statement

In the last few decades, loaded differential equations with boundary conditions have been studied by many researchers [1,2,3, 4,5,6, 7,8,9, 10,11]. This is because, loaded equations describe problems in optimal control, regulation of the layer of soil water and ground moisture, and underground fluid and gas dynamics. Monographs [12,13] contain various applications of loaded equations as a method for studying problems in mathematical biology, mathematical physics, the theory of mathematical modeling of nonlocal processes and phenomena, and the theory of elastic shells.

Various problems for loaded differential equations with integral conditions and methods for finding their solutions are considered in [14,15,16, 17,18,19, 20,21]. Boundary value problems with integro-multipoint boundary conditions have been studied by many researchers, for example, see [22,23].

In a recent article [24], the author discussed the numerical method for solving the boundary value problem for essentially loaded differential equations based on the Dzhumabaev parametrization method [25,26]. This is a constructive method originally developed to investigate and solve boundary value problems for ordinary differential equations. The Dzhumabaev parametrization method is based on dividing the interval [ 0 , T ] into N parts and introducing the additional parameters. In [25], coefficient criteria were established for the unique solvability of linear boundary value problems. An algorithm for finding their approximate solutions was developed. The Dzhumabaev parametrization method was later extended to boundary value problems, both linear and nonlinear, for various classes of equations. In [24], the term essentially loaded differential equation means that the right side of the differential equation depends on the value of the desired solution and its derivatives at given points, where the order of the derivatives is not less than the order of the differential part of the equation. In [24], by assuming the invertibility of the matrix compiled through the coefficients at the values of the derivative of the desired function at load points, we reduce the considering problem to a two-point boundary value problem for loaded differential equations.

Motivated by the research going on in this direction, in this article, we study the finding a numerical solution to the linear boundary value problem for systems of essentially loaded differential equations with an integro-multipoint condition of the form:

(1) d x d t = A 0 ( t ) x + i = 1 m A i ( t ) x ˙ ( θ i ) + f ( t ) , t ( 0 , T ) ,

(2) j = 0 m + 1 B j x ( θ j ) + θ 0 θ m + 1 C ( t ) x ( t ) d t = d , d R n , x R n .

Here, ( n × n ) -matrices A i ( t ) , ( i = 0 , m ¯ ) , C ( t ) , and n -vector-function f ( t ) are continuous on [ 0 , T ] , B j ( j = 0 , m + 1 ¯ ) are constant ( n × n ) -matrices, and 0 = θ 0 < θ 1 < < θ m < θ m + 1 = T ; x = max i = 1 , n ¯ x i .

Let C ( [ 0 , T ] , R n ) denote the space of continuous functions x : [ 0 , T ] R n with the norm x 1 = max t [ 0 , T ] x ( t ) .

A solution to problem (1), (2) is a continuously differentiable on ( 0 , T ) function x ( t ) C ( [ 0 , T ] , R n ) satisfying the system of essentially loaded differential equations (1) and the integro-multipoint condition (2).

The aim of this article is to propose a numerical implementation of the Dzhumabaev parametrization method for solving the boundary value problem for systems of essentially loaded differential equations with integro-multipoint condition (1), (2).

1.1 The scheme of the Dzhumabaev parametrization method

Definition 1

Problem (1), (2) is called uniquely solvable, if for any function f ( t ) C ( [ 0 , T ] , R n ) and vector d R n , it has a unique solution.

The interval [ 0 , T ] is partitioned by the loading points: [ 0 , T ) = r = 1 m + 1 [ θ r 1 , θ r ) .

Let C ( [ 0 , T ] , θ , R n ( m + 1 ) ) denote the space of function systems x [ t ] = ( x 1 ( t ) , x 2 ( t ) , , x m + 1 ( t ) ) , where x r : [ θ r 1 , θ r ) R n are continuous on [ θ r 1 , θ r ) and have finite left-sided limits lim t θ r 0 x r ( t ) for all r = 1 , m + 1 ¯ , with the norm x [ ] 2 = max r = 1 , m + 1 ¯ sup t [ θ r 1 , θ r ) x r ( t ) .

The restriction of the function x ( t ) to the r th subinterval [ θ r 1 , θ r ) is denoted by x r ( t ) , i.e., x r ( t ) = x ( t ) for t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , and the restriction of the function x ˙ ( t ) to the r th subinterval [ θ r 1 , θ r ) is denoted by x ˙ r ( t ) , i.e., x ˙ r ( t ) = x ˙ ( t ) for t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ . The problem (1), (2) is then transformed into the equivalent problem:

(3) d x r d t = A 0 ( t ) x r + i = 1 m A i ( t ) x ˙ i + 1 ( θ i ) + f ( t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ ,

(4) j = 0 m B j x j + 1 ( θ j ) + B m + 1 lim t θ m + 1 0 x m + 1 ( t ) + r = 1 m + 1 θ r 1 θ r C ( t ) x r ( t ) d t = d ,

(5) lim t θ i 0 x i ( t ) = x i + 1 ( θ i ) , i = 1 , m ¯ ,

where (5) are conditions for matching the solution at the interior partition points. From conditions (5) and the assumption of the continuity of the coefficients A i ( t ) , ( i = 0 , m ¯ ) , it follows that the derivatives of the solution will also be continuous at the partition points.

A solution of problem (3)–(5) is a system of functions x [ t ] = ( x 1 ( t ) , x 2 ( t ) , , x m + 1 ( t ) ) C ( [ 0 , T ] , θ , R n ( m + 1 ) ) , where functions x r ( t ) , r = 1 , m + 1 ¯ , are continuously differentiable on [ θ r 1 , θ r ) , which satisfies system (3) and conditions (4) and (5).

Problem (1), (2), and (3)–(5) are equivalent. If a system of functions x ˜ [ t ] = ( x ˜ 1 ( t ) , x ˜ 2 ( t ) , , x ˜ m + 1 ( t ) ) C ( [ 0 , T ] , θ , R n ( m + 1 ) ) is a solution of problem (3)–(5), then the function x ˜ ( t ) defined by the equalities x ˜ ( t ) = x ˜ r ( t ) , x ˜ ˙ ( t ) = x ˜ ˙ r ( t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , and x ˜ ( θ m + 1 ) = lim t θ m + 1 0 x ˜ m + 1 ( t ) is a solution of the original problem (1), (2). Conversely, if x ( t ) is a solution of problem (1), (2), then the system of functions x [ t ] = ( x 1 ( t ) , x 2 ( t ) , , x m + 1 ( t ) ) , where x r ( t ) = x ( t ) , x ˙ r ( t ) = x ˙ ( t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , and lim t θ m + 1 0 x m + 1 ( t ) = x ( θ m + 1 ) is a solution of problem (3)–(5).

Introducing the additional parameters λ r = lim t θ r 1 + 0 x r ( t ) , μ r = lim t θ r 1 + 0 x ˙ r ( t ) , r = 1 , m + 1 ¯ , and performing a replacement of the function u r ( t ) = x r ( t ) λ r on the each interval [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , we obtain the boundary value problem with parameters λ r , r = 1 , m + 1 ¯ :

(6) d u r d t = A 0 ( t ) ( u r + λ r ) + i = 1 m A i ( t ) μ i + 1 + f ( t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ ,

(7) u r ( θ r 1 ) = 0 , r = 1 , m + 1 ¯ ,

(8) j = 0 m B j λ j + 1 + B m + 1 λ m + 1 + B m + 1 lim t θ m + 1 0 u m + 1 ( t ) + r = 1 m + 1 θ r 1 θ r C ( t ) ( u r ( t ) + λ r ) d t = d ,

(9) λ i + lim t θ i 0 u i ( t ) = λ i + 1 , i = 1 , m ¯ ,

(10) lim t θ r 1 + 0 u ˙ r ( t ) = μ r , r = 1 , m + 1 ¯ .

A solution to problem (6)–(10) is a triple ( λ , μ , u [ t ] ) , with elements λ = ( λ 1 , λ 2 , , λ m + 1 ) R n ( m + 1 ) , μ = ( μ 1 , μ 2 , , μ m + 1 ) R n ( m + 1 ) , and u [ t ] = ( u 1 ( t ) , u 2 ( t ) , , u m + 1 ( t ) ) C ( [ 0 , T ] , θ , R n ( m + 1 ) ) , where u r ( t ) are continuously differentiable on [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , and satisfying the system of ordinary differential equations (6) and conditions (7)–(10) at the λ r = λ r , μ r = μ r , j = 1 , m + 1 ¯ .

Problem (1), (2) are equivalent to problem (6)–(10). If the function x ( t ) is a solution to problem (1), (2), then the triple ( λ , μ , u [ t ] ) , where λ = ( x ( θ 0 ) , x ( θ 1 ) , , x ( θ m ) ) , μ = ( x ˙ ( θ 0 ) , x ˙ ( θ 1 ) , , x ˙ ( θ m ) ) , and u [ t ] = ( x ( t ) x ( θ 0 ) , x ( t ) x ( θ 1 ) , , x ( t ) x ( θ m ) ) is a solution to problem (6)–(10). Conversely, if the triple ( λ ˜ , μ ˜ , u ˜ [ t ] ) , with elements λ ˜ = ( λ ˜ 1 , λ ˜ 2 , , λ ˜ m + 1 ) R n ( m + 1 ) , μ ˜ = ( μ ˜ 1 , μ ˜ 2 , , μ ˜ m + 1 ) R n ( m + 1 ) , u ˜ [ t ] = ( u ˜ 1 ( t ) , u ˜ 2 ( t ) , , u ˜ m + 1 ( t ) ) C ( [ 0 , T ] , θ , R n ( m + 1 ) ) , is a solution to problem (6)–(10), then the function x ˜ ( t ) defined by the equalities x ˜ ( t ) = u ˜ r ( t ) + λ ˜ r , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ , and x ˜ ( T ) = λ ˜ m + 1 + lim t T 0 u ˜ m + 1 ( t ) will be the solution of the original problem (1), (2).

First, find the values of μ j , j = 1 , m + 1 ¯ . By passing on the right-hand side of (6) to the limit as t θ r 1 + 0 and r = 1 , m + 1 ¯ , and substituting the expression into (10), we obtain the system of equations for the unknown parameters μ j , j = 1 , m + 1 ¯ :

(11) μ r i = 1 m A i ( θ r 1 ) μ i + 1 = A 0 ( θ r 1 ) λ r + f ( θ r 1 ) , r = 1 , m + 1 ¯ ,

that is, we can rewrite equation (11) in the following form:

(12) G ( θ ) μ = H ( θ , λ ) , μ R n ( m + 1 ) .

Here,

G ( θ ) = I A 1 ( θ 0 ) A 2 ( θ 0 ) A m 1 ( θ 0 ) A m ( θ 0 ) O I A 1 ( θ 1 ) A 2 ( θ 1 ) A m 1 ( θ 1 ) A m ( θ 1 ) O A 1 ( θ 2 ) I A 2 ( θ 2 ) A m 1 ( θ 2 ) A m ( θ 2 ) O A 1 ( θ m 1 ) A 2 ( θ m 1 ) I A m 1 ( θ m 1 ) A m ( θ m 1 ) O A 1 ( θ m ) A 2 ( θ m ) A m 1 ( θ m ) I A m ( θ m ) ,

where I is the identity matrix of dimension n and O is the zero matrix of dimension n ,

H ( θ , λ ) = ( H 1 ( θ , λ ) , H 2 ( θ , λ ) , , H m + 1 ( θ , λ ) ) , H r ( θ , λ ) = A 0 ( θ r 1 ) λ r + f ( θ r 1 ) , r = 1 , m + 1 ¯ .

Assume that the matrix G ( θ ) is invertible. Denote by S ( θ ) the inverse matrix G ( θ ) , i.e., S ( θ ) = [ G ( θ ) ] 1 , where S ( θ ) = s p , k ( θ ) , p , k = 1 , m + 1 ¯ . Then from (12), we can uniquely determine μ :

μ = [ G ( θ ) ] 1 H ( θ , λ ) = S ( θ ) H ( θ , λ ) ,

i.e.,

(13) μ r = k = 1 m + 1 s r , k ( θ ) { A 0 ( θ k 1 ) λ k + f ( θ k 1 ) } , r = 1 , m + 1 ¯ .

In (6), substituting the right-hand side of (13) instead of μ i + 1 , i = 1 , m + 1 ¯ , we obtain

(14) d u r d t = A 0 ( t ) ( u r + λ r ) + j = 1 m + 1 D j ( t ) λ j + F ( t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ ,

where

D j ( t ) = i = 1 m A i ( t ) s i + 1 , j ( θ ) A 0 ( θ j 1 ) , j = 1 , m + 1 ¯ , F ( t ) = i = 1 m k = 1 m + 1 A i ( t ) s i + 1 , k ( θ ) f ( θ k 1 ) + f ( t ) .

Definition 2

The Cauchy problem (14) and (7) is called uniquely solvable, if for any λ R n ( m + 1 ) , f ( t ) C ( [ 0 , T ] , R n ) it has a unique solution.

Let Φ r ( t ) be a fundamental matrix of the differential equation d x d t = A 0 ( t ) x on [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ .

Then the unique solution to the Cauchy problem for the system of ordinary differential equations (14) and (7) with the fixed values

(15) u r ( t ) = Φ r ( t ) θ r 1 t Φ r 1 ( τ ) A 0 ( τ ) d τ λ r + Φ r ( t ) θ r 1 t Φ r 1 ( τ ) j = 1 m + 1 D j ( τ ) d τ λ j + Φ r ( t ) θ r 1 t Φ r 1 ( τ ) F ( τ ) d τ , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ .

As a rule, construction of fundamental matrices for the systems of ordinary differential equations with variable coefficients fails. Therefore, later, we propose a numerical method for solving problem (1), (2). For this purpose, we consider the Cauchy problems for ordinary differential equations on subintervals

(16) d z d t = A ( t ) z + P ( t ) , z ( θ r 1 ) = 0 , t [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ ,

where P ( t ) is either ( n × n ) matrix, or n vector, both continuous on [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ . Consequently, the solution to problem (16) is a square matrix or a vector of dimension n . Denote by a r ( P , t ) a solution to the Cauchy problem (16). Obviously,

(17) a r ( P , t ) = Φ r ( t ) θ r 1 t Φ r 1 ( τ ) P ( τ ) d τ , t [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ ,

where Φ r ( t ) is a fundamental matrix of the differential equation (16) on the r th subinterval.

Now, taking into account (17), we can rewrite (15) in the following form:

(18) u r ( t ) = a r ( A 0 , t ) λ r + j = 1 m + 1 a r ( D j , t ) λ j + a r ( F , t ) , t [ θ r 1 , θ r ) , r = 1 , m + 1 ¯ .

Substituting the right-hand side of (18) into conditions (8) and (9), at the corresponding limit values, we obtain the following system of linear algebraic equations with respect to parameters λ r , r = 1 , m + 1 ¯ :

(19) j = 0 m B j λ j + 1 + B m + 1 λ m + 1 + B m + 1 { a m + 1 ( A 0 , θ m + 1 ) λ m + 1 + j = 1 m + 1 a m + 1 ( D j , θ m + 1 ) λ j } + r = 1 m + 1 θ r 1 θ r C ( t ) λ r d t + r = 1 m + 1 θ r 1 θ r C ( t ) { a r ( A 0 , t ) λ r + j = 1 m + 1 a r ( D j , t ) λ j } d t = d B m + 1 a m + 1 ( F , θ m + 1 ) r = 1 m + 1 θ r 1 θ r C ( t ) a r ( F , t ) d t ,

(20) λ i + a i ( A 0 , θ i ) λ i + j = 1 m + 1 a i ( D j , θ i ) λ j λ i + 1 = a i ( F , θ i ) , i = 1 , m ¯ .

We denote the matrix corresponding to the left-hand side of the system of equations (19) and (20) by Q ( θ ) and write the system in the following form:

(21) Q ( θ ) λ = F ( θ ) , λ R n ( m + 1 ) ,

where F ( θ ) = ( d B m + 1 a m + 1 ( F , θ m + 1 ) r = 1 m + 1 θ r 1 θ r C ( t ) a r ( F , t ) d t , a 1 ( F , θ 1 ) , , a m ( F , θ m ) ) ,

Q ( θ ) = ( Q p , k ( θ ) ) , p , k = 1 , m + 1 ¯ , i.e. , Q 1 , 1 ( θ ) = B 0 + B m + 1 a m + 1 ( D 1 , θ m + 1 ) + θ 0 θ 1 C ( t ) d t + θ 0 θ 1 C ( t ) a 1 ( A 0 , t ) d t + r = 1 m + 1 θ r 1 θ r C ( t ) a r ( D 1 , t ) d t , Q 1 , k ( θ ) = B k 1 + B m + 1 a m + 1 ( D k , θ m + 1 ) + θ k 1 θ k C ( t ) d t + θ k 1 θ k C ( t ) a k ( A 0 , t ) d t + r = 1 m + 1 θ r 1 θ r C ( t ) a r ( D k , t ) d t , k = 2 , m ¯ , Q 1 , m + 1 ( θ ) = B m + B m + 1 + B m + 1 a m + 1 ( A 0 , θ m + 1 ) + B m + 1 a m + 1 ( D m + 1 , θ m + 1 ) + θ m θ m + 1 C ( t ) d t + θ m θ m + 1 C ( t ) a m + 1 ( A 0 , t ) d t + r = 1 m + 1 θ r 1 θ r C ( t ) a r ( D m + 1 , t ) d t , Q p , p 1 ( θ ) = I + a p 1 ( A 0 , θ p 1 ) + a p 1 ( D p 1 , θ p 1 ) , p = 2 , m + 1 ¯ , Q p , p ( θ ) = a p 1 ( D p , θ p 1 ) I , p = 2 , m + 1 ¯ , Q p , k ( θ ) = a p 1 ( D k , θ p 1 ) , k p , k p 1 , k = 1 , m + 1 ¯ , p = 2 , m + 1 ¯ .

1.2 Numerical implementation of the method

We offer the following numerical implementation of the Dzhumabaev parametrization method for solving linear boundary value problem for essentially loaded differential equations with integro-multipoint condition based on the Runge-Kutta method of fourth-order and Simpson’s method.

  1. Suppose we have a partition: 0 = θ 0 < θ 1 < θ 2 < < θ m 1 < θ m < θ m + 1 = T . Divide each r th interval [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ , into N r parts with step size h r = ( θ r θ r 1 ) N r . Assume that on each interval [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ , the variable θ ^ takes its discrete values: θ ^ = θ r 1 , θ ^ = θ r 1 + h r , , θ ^ = θ r 1 + ( N r 1 ) h r , θ ^ = θ r , and denote by { θ r 1 , θ r } , r = 1 , m + 1 ¯ , the set of such points.

  2. We find the values of ( n × n ) matrices a r ( A 0 , θ ^ ) , a r ( D i , θ ^ ) , i = 1 , m + 1 ¯ , and n vector a r ( F , θ ^ ) on { θ r 1 , θ r } , r = 1 , m + 1 ¯ .

  3. Applying Simpson’s method on the set { θ r 1 , θ r } , r = 1 , m + 1 ¯ , we evaluate the definite integrals

    W r ( C ) = θ r 1 θ r C ( t ) d t , W r ( F ) = θ r 1 θ r C ( t ) a r ( F , t ) d t , r = 1 , m + 1 ¯ , W r ( A 0 ) = θ r 1 θ r C ( t ) a r ( A 0 , t ) d t , W r ( D j ) = θ r 1 θ r C ( t ) a r ( D j , t ) d t , j = 1 , m + 1 ¯ .

  4. Construct the system of linear algebraic equations in parameters

    (22) Q h ˜ ( θ ) λ = F h ˜ ( θ ) , λ R n ( m + 1 ) ,

    and find its solution λ h ˜ . As noted earlier, the elements of λ h ˜ = ( λ 1 h ˜ , λ 2 h ˜ , , λ m h ˜ , λ m + 1 h ˜ ) are the values of an approximate solution to problem (1), (2) at the left end-points of the subintervals: x h ˜ r ( θ r 1 ) = λ r h ˜ , r = 1 , m + 1 ¯ .

  5. To define the values of an approximate solution at the remaining points of set { θ r 1 , θ r } , r = 1 , m + 1 ¯ , we solve the Cauchy problems:

    d x d t = A 0 ( t ) x + j = 1 m + 1 D j ( t ) λ j h ˜ + F ( t ) , x ( θ r 1 ) = λ r h ˜ , t [ θ r 1 , θ r ] , r = 1 , m + 1 ¯ .

    We found the solutions to Cauchy problems by using the fourth-order Runge-Kutta method. Thus, the algorithm allows us to find the numerical solution to the problem (1), (2), when the matrices G ( θ ) , Q ( θ ) are invertible.

1.3 Solvability of the problem

In this section, we establish conditions for the unique solvability of problem (1), (2). To prove the main assertion, we need the following lemma.

Lemma 1

If G ( θ ) is invertible, then the following assertions hold:

  1. If λ ˜ R n ( m + 1 ) and μ ˜ R n ( m + 1 ) are solutions of systems (21) and (12), respectively, and the function system u ˜ [ t ] C ( [ 0 , T ] , θ , R n ( m + 1 ) ) is a solution to the Cauchy problem (6), (7) with λ r = λ ˜ r , μ r = μ ˜ r , r = 1 , m + 1 ¯ , then the function x ˜ ( t ) , defined by the equalities:

    x ˜ ( t ) = u ˜ r ( t ) + λ ˜ r , t [ θ r 1 , θ r ) , lim t θ r 1 + 0 x ˜ ˙ ( t ) = μ ˜ r , r = 1 , m + 1 ¯ , x ˜ ( T ) = λ ˜ m + 1 + lim t T 0 u ˜ m + 1 ( t ) ,

    is a solution to problem (1), (2);

  2. The vectors λ R n ( m + 1 ) and μ R n ( m + 1 ) , composed of the values of the solution x ( t ) and its derivative x ˙ ( t ) to problem (1), (2) at the partition points λ r = lim t θ r 1 + 0 x ( t ) , and μ r = lim t θ r 1 + 0 x ˙ ( t ) , r = 1 , m + 1 ¯ , satisfy the systems (21) and (12), respectively.

The evidence is similar in concept to the proof of Lemma 1 with slight variations [27].

We present the main theorem on the existence of a unique solution to problem (1), (2) in terms of matrices G ( θ ) and Q ( θ ) .

Theorem 1

Let the matrices G ( θ ) : R n ( m + 1 ) R n ( m + 1 ) and Q ( θ ) : R n ( m + 1 ) R n ( m + 1 ) be invertible. Then boundary value problem (1), (2) has a unique solution x ( t ) for any f ( t ) C ( [ 0 , T ] , R n ) , d R n .

Proof

Let f ( t ) C ( [ 0 , T ] , R n ) and d R n . We find an unique solution to the systems (12) and (21), using the invertibility of matrices G ( θ ) and Q ( θ ) : μ = [ G ( θ ) ] 1 P ( θ , λ ) and λ = [ Q ( θ ) ] 1 F ( θ ) . Solving the Cauchy problem (6), (7) with λ = λ and μ = μ , define the function system u [ t ] . The invertibility of the matrices G ( θ ) and Q ( θ ) lead to the existence of unique function system u [ t ] with the elements u r [ t ] , defined by the right-hand side of (15) at λ = λ . Then, according to Lemma 1, the function x ( t ) , defined by the equalities: x ( t ) = u r ( t ) + λ r , t [ θ r 1 , θ r ) , lim t θ r 1 + 0 x ˙ ( t ) = μ r , r = 1 , m + 1 ¯ , x ( T ) = λ m + 1 + lim t T 0 u m + 1 ( t ) , is a solution to problem (1), (2). Uniqueness of the solution is proved by contradiction. Theorem 1 is proved.□

To illustrate the fulfillment of the theorem’s conditions and the proposed approach of the numerical solving of the boundary value problem for systems of essentially loaded differential equations with integro-multipoint condition (1), (2) based on the Dzhumabaev parametrization method, let us consider the following examples.

1.4 Examples

Example 1

We consider a linear boundary value problem for essentially loaded differential equations with an integro-multipoint condition:

(23) d x d t = A 0 ( t ) x + A 1 ( t ) x ˙ ( θ 1 ) + A 2 ( t ) x ˙ ( θ 2 ) + A 3 ( t ) x ˙ ( θ 3 ) + f ( t ) , t ( 0 , 1 ) ,

(24) j = 0 4 B j x ( θ j ) + θ 0 θ 4 C ( t ) x ( t ) d t = d , d R 3 , x R 3 .

Here,

θ 0 = 0 , θ 1 = 1 4 , θ 2 = 1 2 , θ 3 = 3 4 , θ 4 = T = 1 , f ( t ) = 36 t 108 t 3 132 t 2 48 t 4 396 48 t 2 90 t 3 12 t 4 252 t 696 360 t 4 228 t 3 108 t 2 408 t 54 ,

A 0 ( t ) = t 2 t 2 t 1 t 3 0 3 t 2 5 6 t , A 1 ( t ) = 1 t t 2 4 t 6 0 3 t 4 t 2 , A 2 ( t ) = t 0 6 t 2 4 5 0 t 5 7 t , A 3 ( t ) = t 2 3 t 0 t + 2 6 7 0 t 3 1 , B 0 = 1 4 5 6 3 2 8 0 1 , B 1 = 3 0 5 3 2 1 5 3 5 , B 2 = 1 6 8 3 0 7 6 4 2 , B 3 = 5 0 6 2 1 6 4 6 8 , B 4 = 2 6 7 6 0 5 5 11 3 , C ( t ) = t 8 0 4 2 1 0 3 t 5 , d = 368 869 454 .

We use the numerical implementation of algorithm. The accuracy of the solution depends on the accuracy of solving the Cauchy problem on subintervals and evaluating definite integrals. We provide the results of the numerical implementation of algorithm by partitioning the subintervals [ 0 , 0.25 ] , [ 0.25 , 0.5 ] , [ 0.5 , 0.75 ] , [ 0.75 , 1 ] with step h = 0.025 . Solving the system of equations (22), we obtain the numerical values of the parameters

λ 1 h ˜ = 12.00002405 6.00001267 0.0000129 , λ 2 h ˜ = 12.00002727 3.00001292 6.00000624 , λ 3 h ˜ = 24.00002692 0.00001382 18.00000584 , λ 4 h ˜ = 48.00001942 2.99998431 36.00000785 .

Exact solution of problem (23) and (24) is the following: x ( t ) = 96 t 2 24 t + 12 12 t 6 48 t 2 + 12 t .

The differences between the exact and approximate solutions to problem (23) and (24)  ε i = x ( i ) ( t k ) x ˜ ( i ) ( t k ) , i = 1 , 3 ¯ , are provided in Table 1. Table 2 provides the difference between numerical and exact solutions of problem (23) and (24), where we solve Cauchy problems by using the Runge-Kutta Fehlberg method.

Table 1

Error analysis in Example 1 (using the fourth-order Runge-Kutta method)

k t k ε 1 ε 2 ε 3 k t k ε 1 ε 2 ε 3
0 0 2.4 × 1 0 5 1.27 × 1 0 5 1.29 × 1 0 5 20 0.5 2.69 × 1 0 5 1.38 × 1 0 5 0.58 × 1 0 5
1 0.025 2.45 × 1 0 5 1.27 × 1 0 5 1.19 × 1 0 5 21 0.525 2.66 × 1 0 5 1.39 × 1 0 5 0.61 × 1 0 5
2 0.05 2.49 × 1 0 5 1.27 × 1 0 5 1.09 × 1 0 5 22 0.55 2.62 × 1 0 5 1.41 × 1 0 5 0.63 × 1 0 5
3 0.075 2.52 × 1 0 5 1.27 × 1 0 5 1.01 × 1 0 5 23 0.575 2.57 × 1 0 5 1.42 × 1 0 5 0.66 × 1 0 5
4 0.1 2.56 × 1 0 5 1.27 × 1 0 5 0.93 × 1 0 5 24 0.6 2.51 × 1 0 5 1.44 × 1 0 5 0.69 × 1 0 5
5 0.125 2.59 × 1 0 5 1.27 × 1 0 5 0.86 × 1 0 5 25 0.625 2.44 × 1 0 5 1.46 × 1 0 5 0.72 × 1 0 5
6 0.15 2.63 × 1 0 5 1.27 × 1 0 5 0.8 × 1 0 5 26 0.65 2.36 × 1 0 5 1.48 × 1 0 5 0.74 × 1 0 5
7 0.175 2.66 × 1 0 5 1.28 × 1 0 5 0.75 × 1 0 5 27 0.675 2.28 × 1 0 5 1.5 × 1 0 5 0.77 × 1 0 5
8 0.2 2.68 × 1 0 5 1.28 × 1 0 5 0.7 × 1 0 5 28 0.7 2.18 × 1 0 5 1.52 × 1 0 5 0.78 × 1 0 5
9 0.225 2.71 × 1 0 5 1.29 × 1 0 5 0.66 × 1 0 5 29 0.725 2.07 × 1 0 5 1.54 × 1 0 5 0.79 × 1 0 5
10 0.25 2.73 × 1 0 5 1.29 × 1 0 5 0.62 × 1 0 5 30 0.75 1.94 × 1 0 5 1.57 × 1 0 5 0.79 × 1 0 5
11 0.275 2.74 × 1 0 5 0.13 × 1 0 5 0.59 × 1 0 5 31 0.775 1.8 × 1 0 5 1.6 × 1 0 5 0.76 × 1 0 5
12 0.3 2.76 × 1 0 5 1.31 × 1 0 5 0.57 × 1 0 5 32 0.8 1.65 × 1 0 5 1.63 × 1 0 5 0.71 × 1 0 5
13 0.325 2.77 × 1 0 5 1.31 × 1 0 5 0.55 × 1 0 5 33 0.825 1.47 × 1 0 5 1.67 × 1 0 5 0.63 × 1 0 5
14 0.35 2.77 × 1 0 5 1.32 × 1 0 5 0.54 × 1 0 5 34 0.85 1.28 × 1 0 5 1.71 × 1 0 5 0.51 × 1 0 5
15 0.375 2.77 × 1 0 5 1.33 × 1 0 5 0.54 × 1 0 5 35 0.875 1.06 × 1 0 5 1.75 × 1 0 5 0.34 × 1 0 5
16 0.4 2.77 × 1 0 5 1.34 × 1 0 5 0.54 × 1 0 5 36 0.9 0.82 × 1 0 5 1.8 × 1 0 5 0.1 × 1 0 5
17 0.425 2.76 × 1 0 5 1.35 × 1 0 5 0.54 × 1 0 5 37 0.925 0.54 × 1 0 5 1.85 × 1 0 5 0.22 × 1 0 5
18 0.45 2.74 × 1 0 5 1.36 × 1 0 5 0.55 × 1 0 5 38 0.95 0.23 × 1 0 5 1.91 × 1 0 5 0.66 × 1 0 5
19 0.475 2.72 × 1 0 5 1.37 × 1 0 5 0.57 × 1 0 5 39 0.975 0.12 × 1 0 5 1.98 × 1 0 5 1.23 × 1 0 5
20 0.5 2.69 × 1 0 5 1.38 × 1 0 5 0.58 × 1 0 5 40 1 0.53 × 1 0 5 2.06 × 1 0 5 1.97 × 1 0 5
Table 2

Error analysis in Example 1 (using the Runge-Kutta Fehlberg method)

k t k ε 1 ε 2 ε 3 k t k ε 1 ε 2 ε 3
0 0 1.11 × 1 0 9 8.88 × 1 0 10 1.46 × 1 0 9 20 0.5 1.35 × 1 0 9 1.02 × 1 0 9 8.27 × 1 0 10
1 0.025 1.14 × 1 0 9 8.92 × 1 0 10 1.39 × 1 0 9 21 0.525 1.32 × 1 0 9 1.03 × 1 0 9 8.19 × 1 0 10
2 0.05 1.17 × 1 0 9 8.97 × 1 0 10 1.32 × 1 0 9 22 0.55 1.30 × 1 0 9 1.04 × 1 0 9 8.22 × 1 0 10
3 0.075 1.19 × 1 0 9 9.02 × 1 0 10 1.26 × 1 0 9 23 0.575 1.27 × 1 0 9 1.05 × 1 0 9 8.27 × 1 0 10
4 0.1 1.22 × 1 0 9 9.07 × 1 0 10 1.21 × 1 0 9 24 0.6 1.24 × 1 0 9 1.06 × 1 0 9 8.35 × 1 0 10
5 0.125 1.24 × 1 0 9 9.13 × 1 0 10 1.16 × 1 0 9 25 0.625 1.20 × 1 0 9 1.07 × 1 0 9 8.45 × 1 0 10
6 0.15 1.27 × 1 0 9 9.19 × 1 0 10 1.11 × 1 0 9 26 0.65 1.15 × 1 0 9 1.09 × 1 0 9 8.57 × 1 0 10
7 0.175 1.29 × 1 0 9 9.25 × 1 0 10 1.07 × 1 0 9 27 0.675 1.10 × 1 0 9 1.10 × 1 0 9 8.72 × 1 0 10
8 0.2 1.31 × 1 0 9 9.32 × 1 0 10 1.03 × 1 0 9 28 0.7 1.04 × 1 0 9 1.11 × 1 0 9 8.88 × 1 0 10
9 0.225 1.33 × 1 0 9 9.38 × 1 0 10 9.97 × 1 0 10 29 0.725 9.80 × 1 0 10 1.13 × 1 0 9 9.05 × 1 0 10
10 0.25 1.34 × 1 0 9 9.45 × 1 0 10 9.65 × 1 0 10 30 0.75 9.07 × 1 0 10 1.14 × 1 0 9 9.23 × 1 0 10
11 0.275 1.36 × 1 0 9 9.52 × 1 0 10 9.50 × 1 0 10 31 0.775 8.00 × 1 0 10 1.16 × 1 0 9 7.98 × 1 0 10
12 0.3 1.37 × 1 0 9 9.59 × 1 0 10 9.25 × 1 0 10 32 0.8 7.08 × 1 0 10 1.18 × 1 0 9 7.96 × 1 0 10
13 0.325 1.38 × 1 0 9 9.67 × 1 0 10 9.03 × 1 0 10 33 0.825 6.08 × 1 0 10 1.20 × 1 0 9 7.89 × 1 0 10
14 0.35 1.38 × 1 0 9 9.75 × 1 0 10 8.83 × 1 0 10 34 0.85 4.96 × 1 0 10 1.22 × 1 0 9 7.74 × 1 0 10
15 0.375 1.38 × 1 0 9 9.83 × 1 0 10 8.67 × 1 0 10 35 0.875 3.74 × 1 0 10 1.25 × 1 0 9 7.49 × 1 0 10
16 0.4 1.38 × 1 0 9 9.91 × 1 0 10 8.53 × 1 0 10 36 0.9 2.38 × 1 0 10 1.28 × 1 0 9 7.09 × 1 0 10
17 0.425 1.38 × 1 0 9 9.99 × 1 0 10 8.42 × 1 0 10 37 0.925 8.99 × 1 0 11 1.31 × 1 0 9 6.51 × 1 0 10
18 0.45 1.37 × 1 0 9 1.01 × 1 0 9 8.34 × 1 0 10 38 0.95 7.39 × 1 0 11 1.35 × 1 0 9 5.69 × 1 0 10
19 0.475 1.36 × 1 0 9 1.02 × 1 0 9 8.29 × 1 0 10 39 0.975 2.55 × 1 0 10 1.39 × 1 0 9 4.56 × 1 0 10
20 0.5 1.35 × 1 0 9 1.02 × 1 0 9 8.27 × 1 0 10 40 1 4.55 × 1 0 10 1.43 × 1 0 9 3.02 × 1 0 10

From Tables 1 and 2, it can be seen that the Runge-Kutta Fehlberg method is able to produce lower error rates compared with those from the fourth-order Runge-Kutta method. All results were received by using MathCad15.

Example 2

We consider a linear boundary value problem for essentially loaded differential equations with an integro-multipoint condition:

(25) d x d t = t 1 0 2 t 2 x + 1 2 t t 3 0 x ˙ 1 4 + 0 t 4 t + 3 1 x ˙ 1 2 + 3 t 6 t 2 2 x ˙ 3 4 + 64 t 3 33 t 4 9 t 2 + 1,039 16 t 3,139 16 1,509 16 t 2 131 16 t 3 24 t 4 + 349 4 t + 407 4 , t ( 0 , 1 ) ,

(26) 1 0 3 5 x ( 0 ) + 3 8 1 3 x 1 4 + 2 3 5 7 x 1 2 + 9 0 3 5 x 3 4 + 1 6 7 3 x ( 1 ) + 0 1 t 2 4 1 7 t x ( t ) d t = 761 30 8,495 96 , x R 2 .

The exact solution of problem (25) and (26) is the following: x ( t ) = t 3 64 t 2 + 18 12 t 2 + 20 t .

We use the numerical implementation of algorithm. The accuracy of the solution depends on the accuracy of solving the Cauchy problem on subintervals and evaluating definite integrals. We provide the results of the numerical implementation of algorithm by partitioning the subintervals [ 0 , 0.25 ] , [ 0.25 , 0.5 ] , [ 0.5 , 0.75 ] , [ 0.75 , 1 ] with step h 1 = 0.025 . For the difference of the corresponding values of the exact and constructed solutions of the problem, the following estimate is true:

max j = 0 , 40 ¯ x ( t j ) x ˜ ( t j ) < 0.0000014 .

With step h 2 = 0.0125 :

max j = 0 , 80 ¯ x ( t j ) x ˜ ( t j ) < 0.000000088 .

With step h 3 = 0.00625 :

max j = 0 , 160 ¯ x ( t j ) x ˜ ( t j ) < 0.0000000055 .

With step h 4 = 0.003125 :

max j = 0 , 320 ¯ x ( t j ) x ˜ ( t j ) < 0.00000000034 .



Acknowledgments

The authors thank the reviewers for their constructive remarks on our work.

  1. Funding information: This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP09058457).

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

References

[1] A. M. Nakhushev, Loaded Equations and Their Applications, Nauka, Moscow, 2012 (in Russian). Search in Google Scholar

[2] A. M. Krall, The development of general differential and general differential-boundary systems, Rocky Mt. J. Math. 5 (1975), no. 4, 493–542, https://doi.org/10.1216/RMJ-1975-5-4-493. Search in Google Scholar

[3] D. S. Dzhumabaev, E. A. Bakirova, and S. T. Mynbayeva, A method of solving a nonlinear boundary value problem with a parameter for a loaded differential equation, Math. Methods Appl. Sci. 43 (2020), no. 4, 1788–1802, DOI: https://doi.org/10.1002/mma.6003. 10.1002/mma.6003Search in Google Scholar

[4] A. M. Nakhushev, A method for approximate solution of boundary value problems for differential equations and its applications to the dynamics of soil moisture and groundwater, Differ. Equ. 18 (1982), 72–81 (in Russian). Search in Google Scholar

[5] A. A. Alikhanov, A. M. Berezkov, and M. Kh. Shkhanukhov-Lafishev, boundary value problems for certain classes of loaded differential equations and solving them by finite difference methods, Comput. Math. Math. Phys. 48 (2005), no. 9, 1581–1590, https://doi.org/10.1134/S096554250809008X. Search in Google Scholar

[6] A. T. Assanova and Zh. M. Kadirbayeva, On the numerical algorithms of parametrization method for solving a two-point boundary-value problem for impulsive systems of loaded differential equations, Comput. Appl. Math. 37 (2018), 4966–4976, https://doi.org/10.1007/s40314-018-0611-9. Search in Google Scholar

[7] T. K. Yuldashev and O. Kh. Abdullaev, Unique solvability of a boundary value problem for a loaded fractional parabolic-hyperbolic equation with nonlinear terms, Lobachevskii J. Math. 42 (2021), no. 5, 1113–1123, DOI: https://doi.org/10.1134/S1995080221050218. 10.1134/S1995080221050218Search in Google Scholar

[8] T. K. Yuldashev, B. I. Islomov, and E. K. Alikulov, Boundary-value problems for loaded third-order parabolic-hyperbolic equations in infinite three-dimensional domains, Lobachevskii J. Math. 41 (2020), no. 5, 926–944, DOI: https://doi.org/10.1134/S1995080220050145. 10.1134/S1995080220050145Search in Google Scholar

[9] U. Baltaeva, Solvability of the analogs of the problem Tricomi for the mixed type loaded equations with parabolic-hyperbolic operators, Bound. Value Probl. 2014 (2014), 211, https://doi.org/10.1186/s13661-014-0211-6. Search in Google Scholar

[10] A. T. Assanova, A. E. Imanchiyev, and Zh. M. Kadirbayeva, Numerical solution of systems of loaded ordinary differential equations with multipoint conditions, Comput. Math. Math. Phys. 58 (2018), 508–516, DOI: https://doi.org/10.1134/S096554251804005X. 10.1134/S096554251804005XSearch in Google Scholar

[11] A. T. Assanova and Zh. M. Kadirbayeva, Periodic problem for an impulsive system of the loaded hyperbolic equations, Electron. J. Differential Equations 2018 (2018), no. 72, 1–8. 10.1063/1.5000620Search in Google Scholar

[12] A. M. Nakhushev, Equations of Mathematical Biology, Vyshaiya shkola, Moscow, 1995 (in Russian). Search in Google Scholar

[13] M. T. Dzhenaliev and M. I. Ramazanov, Loaded Equations as Perturbations of Differential Equations, Gylym, Almaty, 2010 (in Russian). Search in Google Scholar

[14] V. M. Abdullaev and K. R. Aida-zade, Numerical method of solution to loaded nonlocal boundary value problems for ordinary differential equations, Comput. Math. Math. Phys. 54 (2014), 1096–1109, DOI: https://doi.org/10.1134/S0965542514070021. 10.1134/S0965542514070021Search in Google Scholar

[15] V. M. Abdullaev and K. R. Aida-zade, On the numerical solution to loaded systems of ordinary differential equations with non-separated multipoint and integral conditions, Numer. Anal. Appl. 7 (2014), no. 1, 1–14, DOI: https://doi.org/10.1134/S1995423914010017. 10.1134/S1995423914010017Search in Google Scholar

[16] V. M. Abdullaev and K. R. Aida-zade, Solution to a class of inverse problems for a system of loaded ordinary differential equations with integral conditions, J. Inverse Ill-Posed Probl. 24 (2016), no. 5, 543–558, DOI: https://doi.org/10.1515/jiip-2015-0011. 10.1515/jiip-2015-0011Search in Google Scholar

[17] I. N. Parasidis, Extension method for a class of loaded differential equations with nonlocal integral boundary conditions, Bullet. Karaganda Univ. 96 (2019), no. 4, 58–68. 10.31489/2019M4/58-68Search in Google Scholar

[18] I. N. Parasidis and E. Providas, An exact solution method for a class of nonlinear loaded difference equations with multipoint boundary conditions, J. Differential Equations Appl. 24 (2018), no. 10, 1649–1663, DOI: https://doi.org/10.1080/10236198.2018.1515928. 10.1080/10236198.2018.1515928Search in Google Scholar

[19] I. N. Parasidis, E. Providas, and V. Dafopoulos, Loaded differential and Fredholm integro-differential equations with nonlocal integral boundary conditions, Appl. Math. Control Sci. 3 (2018), 50–68, https://doi.org/10.15593/2499-9873/2018.3.04. Search in Google Scholar

[20] I. N. Parasidis and E. Providas, Closed-form solutions for some classes of loaded difference equations with initial and nonlocal multipoint conditions, in: N. Daras and T. Rassias (eds), Modern Discrete Mathematics and Analysis, Springer Optimization and Its Applications, vol. 131, Springer, Cham, 2018, pp. 363–387, https://doi.org/10.1007/978-3-319-74325-7_19. Search in Google Scholar

[21] E. Providas and I. N. Parasidis, On the solution of boundary value problems for loaded ordinary differential equations, in: I. N. Parasidis, E. Providas, and T. M. Rassias (eds), Mathematical Analysis in Interdisciplinary Research, Springer Optimization and Its Applications, vol. 179, Springer, Cham, 2021, pp. 641–659, https://doi.org/10.1007/978-3-030-84721-0_29. Search in Google Scholar

[22] C. Nuchpong, S. K. Ntouyas, and J. Tariboon, Boundary value problems of Hilfer-type fractional integro-differential equations and inclusions with nonlocal integro-multipoint boundary conditions, Open Math. 18 (2020), 1879–1894, https://doi.org/10.1515/math-2020-0122. Search in Google Scholar

[23] A. Alsaedi, B. Ahmad, B. Alghamdi, and S. K. Ntouyas, On a nonlinear system of Riemann-Liouville fractional differential equations with semi-coupled integro-multipoint boundary conditions, Open Math. 19 (2021), 760–772, https://doi.org/10.1515/math-2021-0069. Search in Google Scholar

[24] Zh. M. Kadirbayeva, A numerical method for solving boundary value problem for essentially loaded differential equations, Lobachevskii J. Math 42 (2021), no. 3, 551–559, https://doi.org/10.1134/S1995080221030112. Search in Google Scholar

[25] D. S. Dzhumabaev, Criteria for the unique solvability of a linear boundary-value problem for an ordinary differential equation, USSR Comput. Math. Math. Phys. 29 (1989), 34–46. 10.1016/0041-5553(89)90038-4Search in Google Scholar

[26] S. M. Temesheva, D. S. Dzhumabaev, and S. S. Kabdrakhova, On one algorithm to find a solution to a linear two-point boundary value problem, Lobachevskii J. Math. 42 (2021), no. 3, 606–612, DOI: https://doi.org/10.1134/S1995080221030173. 10.1134/S1995080221030173Search in Google Scholar

[27] D. S. Dzhumabaev, On one approach to solve the linear boundary value problems for Fredholm integro-differential equations, J. Comput. Appl. Math. 294 (2016), 342–357, https://doi.org/10.1016/j.cam.2015.08.023. Search in Google Scholar

Received: 2022-02-22
Revised: 2022-07-21
Accepted: 2022-09-07
Published Online: 2022-10-12

© 2022 Zhazira M. Kadirbayeva and Symbat S. Kabdrakhova, 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 3.11.2025 from https://www.degruyterbrill.com/document/doi/10.1515/math-2022-0496/html?lang=en
Scroll to top button