Yongqing Wang

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Qufu Normal University

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years

University of Wisconsin-Milwaukee

Research Subjects

Research Interests

Yongqing Wang has a total of 14 co-authors. Here are the top co-authors by number of shared publications:

Lishan Liu
School of Mathematical Sciences, Qufu Normal University, Qufu, P.R. China
4 shared publications
Yonghong Wu
Curtin Univ, Dept Math & Stat, Perth, WA 6845, Australia
3 shared publications
Hua Su
School of Mathematics and Quantitative Economics, Shandong University of Finance and Economics, Jinan, Shandong 250014, China
2 shared publications
Jiafa Xu
School of Mathematical Sciences Chongqing Normal University Chongqing China
2 shared publications
Donal O’rEgan
School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
1 shared publication
Haiyan Zhang
School of Mathematics and Statistics, Suzhou University, Suzhou, 234000, Anhui, P.R. China
1 shared publication

Latest Publications

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Cited by 3
- 19 April 2025
- Published by MDPI AG in Fractal and Fractional
Positive Properties of Green’s Function for Fractional Dirichlet Boundary Value Problem with a Perturbation Term and Its Applications
by Yongqing Wang
In this article, we study a fractional lower-order differential equation, $- D_{0 +}^{α} Υ (ξ) + a (ξ) Υ (ξ) = y (ξ), ξ \in (0, 1), α \in (1, 2),$ with a Dirichlet-type boundary condition, where $a (ξ) \in L^{1} [0, 1]$ permits singularity. When the coefficient of perturbation term $a (ξ)$ is continuous on $[0, 1]$ , Graef et al. derived the associated Green’s function under certain conditions on $a$ , but failed to obtain its positivity. We obtain some positive properties of the Green’s function of this problem under certain conditions. The results will fill the gap in the above literature. As for application of the theoretical results, a singular fractional differential equation with a perturbation term is considered. The unique positive solution is obtained by using the fixed point theorem, and an iterative sequence is established to approximate it. In addition, a semipositone fractional differential equation, $- D_{0 +}^{α} Υ (ξ) = μ F (ξ, Υ (ξ)), ξ \in (0, 1), α \in (1, 2),$ is also considered. The existence of positive solutions is determined under a more general condition, $F (ξ, x) \geq - b (ξ) x - e (ξ)$ , where $b (ξ), e (ξ) \in L^{1} [0, 1]$ are non-negative functions. Relevant examples are listed to manifest the theoretical results.
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- 19 April 2025
- Published by MDPI AG in Fractal and Fractional
Open Access
Positive Properties of Green’s Function for Fractional Dirichlet Boundary Value Problem with a Perturbation Term and Its Applications
by Yongqing Wang
In this article, we study a fractional lower-order differential equation, $- D_{0 +}^{α} Υ (ξ) + a (ξ) Υ (ξ) = y (ξ), ξ \in (0, 1), α \in (1, 2),$ with a Dirichlet-type boundary condition, where $a (ξ) \in L^{1} [0, 1]$ permits singularity. When the coefficient of perturbation term $a (ξ)$ is continuous on $[0, 1]$ , Graef et al. derived the associated Green’s function under certain conditions on $a$ , but failed to obtain its positivity. We obtain some positive properties of the Green’s function of this problem under certain conditions. The results will fill the gap in the above literature. As for application of the theoretical results, a singular fractional differential equation with a perturbation term is considered. The unique positive solution is obtained by using the fixed point theorem, and an iterative sequence is established to approximate it. In addition, a semipositone fractional differential equation, $- D_{0 +}^{α} Υ (ξ) = μ F (ξ, Υ (ξ)), ξ \in (0, 1), α \in (1, 2),$ is also considered. The existence of positive solutions is determined under a more general condition, $F (ξ, x) \geq - b (ξ) x - e (ξ)$ , where $b (ξ), e (ξ) \in L^{1} [0, 1]$ are non-negative functions. Relevant examples are listed to manifest the theoretical results.
Cited by 3
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Cited by 1
- 19 February 2025
- Published by MDPI AG in Axioms
Solvability of Singular Fractional-Order Differential Equations with a Perturbation Term
by Linghan Kong, Yongqing Wang
In this article, we study singular fractional-order differential equations with a variable coefficient, namely the linear operator of the differential equation containing a linear term with a variable coefficient. The coefficient $a (s)$ permits singularity at $s = 0, 1$ , and the nonlinearity $f (s, χ)$ may be singular at $s = 0, 1$ and $χ = 0$ . By utilizing the fixed-point index theory, the existence of positive solutions are derived under sharp conditions concerning spectral radius.
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- 19 February 2025
- Published by MDPI AG in Axioms
Open Access
Solvability of Singular Fractional-Order Differential Equations with a Perturbation Term
by Linghan Kong, Yongqing Wang
In this article, we study singular fractional-order differential equations with a variable coefficient, namely the linear operator of the differential equation containing a linear term with a variable coefficient. The coefficient $a (s)$ permits singularity at $s = 0, 1$ , and the nonlinearity $f (s, χ)$ may be singular at $s = 0, 1$ and $χ = 0$ . By utilizing the fixed-point index theory, the existence of positive solutions are derived under sharp conditions concerning spectral radius.
Cited by 1
Open Access
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Cited by 5
- 12 February 2025
- Published by MDPI AG in Fractal and Fractional
A New Result Regarding Positive Solutions for Semipositone Boundary Value Problems of Fractional Differential Equations
by Yongqing Wang
In this paper, we discuss the positive solutions to a class of semipositone boundary value problems of fractional differential equations. The nonlinearity $f (t, x)$ may be singular at $t = 0, 1$ and satisfies $f (t, x) \geq - a (t) x - R (t)$ . We derive some new properties of the Green’s function of the auxiliary problems, and discover the multiplicity and existence of the positive solutions by utilizing the fixed point index theory. Two examples are illustrated to validate the main results.
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- 12 February 2025
- Published by MDPI AG in Fractal and Fractional
Open Access
A New Result Regarding Positive Solutions for Semipositone Boundary Value Problems of Fractional Differential Equations
by Yongqing Wang
In this paper, we discuss the positive solutions to a class of semipositone boundary value problems of fractional differential equations. The nonlinearity $f (t, x)$ may be singular at $t = 0, 1$ and satisfies $f (t, x) \geq - a (t) x - R (t)$ . We derive some new properties of the Green’s function of the auxiliary problems, and discover the multiplicity and existence of the positive solutions by utilizing the fixed point index theory. Two examples are illustrated to validate the main results.
Cited by 5
Open Access
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Cited by 5
- 28 December 2020
- Published by Wiley in Journal of Mathematics
Existence of Solutions for a Periodic Boundary ValueProblem with Impulse and Fractional Derivative Dependence
by Yaohong Li, Yongqing Wang, Donal O’rEgan, Jiafa Xu
In this paper, we present some theorems on impulsive periodic boundary value problems with fractional derivative dependence. In particular, we discuss the existence of solutions of a class of fractional-order impulsive periodic boundary values with nonlinear terms and impulsive terms satisfying certain growth conditions. Three examples are provided to illustrate our results.
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- 28 December 2020
- Published by Wiley in Journal of Mathematics
Open Access
Existence of Solutions for a Periodic Boundary ValueProblem with Impulse and Fractional Derivative Dependence
by Yaohong Li, Yongqing Wang, Donal O’rEgan, Jiafa Xu
In this paper, we present some theorems on impulsive periodic boundary value problems with fractional derivative dependence. In particular, we discuss the existence of solutions of a class of fractional-order impulsive periodic boundary values with nonlinear terms and impulsive terms satisfying certain growth conditions. Three examples are provided to illustrate our results.
Cited by 5
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Cited by 1
- 10 November 2020
- Published by Wiley in Journal of Function Spaces
Infinitely Many High Energy Solutions for the Generalized Chern-Simons-Schrödinger System
by Hua Su, Yongqing Wang, Jiafa Xu
In this paper, by virtue of the critical point theory, we are pleased to investigate the existence of infinitely many high energy solutions for the generalized Chern-Simons-Schrödinger system with a perturbation.
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- 10 November 2020
- Published by Wiley in Journal of Function Spaces
Open Access
Infinitely Many High Energy Solutions for the Generalized Chern-Simons-Schrödinger System
by Hua Su, Yongqing Wang, Jiafa Xu
In this paper, by virtue of the critical point theory, we are pleased to investigate the existence of infinitely many high energy solutions for the generalized Chern-Simons-Schrödinger system with a perturbation.
Cited by 1
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- 24 August 2020
- Published by Wiley in Mathematical Problems in Engineering
Nontrivial Solutions for a System of Second-Order Discrete Boundary Value Problems
by Hua Su, Yongqing Wang, Jiafa Xu
In this work, we shall study the existence of nontrivial solutions for a system of second-order discrete boundary value problems. Under some conditions concerning the eigenvalues of relevant linear operator, we use the topological degree theory to obtain our main results.
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- 24 August 2020
- Published by Wiley in Mathematical Problems in Engineering
Open Access
Nontrivial Solutions for a System of Second-Order Discrete Boundary Value Problems
by Hua Su, Yongqing Wang, Jiafa Xu
In this work, we shall study the existence of nontrivial solutions for a system of second-order discrete boundary value problems. Under some conditions concerning the eigenvalues of relevant linear operator, we use the topological degree theory to obtain our main results.
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Cited by 8
- 3 August 2020
- Published by Springer Nature in Advances in Difference Equations
Explicit monotone iterative sequences for positive solutions of a fractional differential system with coupled integral boundary conditions on a half-line
by Haiyan Zhang, Yongqing Wang, Jiafa Xu
In this paper we consider a fractional differential system with coupled integral boundary value problems on a half-line, where the nonlinearity terms depend on unknown functions and the lower-order fractional derivative of unknown functions, and the fractional infinite boundary value conditions depend on the coupled infinite integral of unknown functions. By virtue of the monotone iterative technique, we find two explicit monotone iterative sequences which converge to the positive minimal and maximal solutions when the nonlinearities can satisfy certain nonlinear growth conditions.
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- 3 August 2020
- Published by Springer Nature in Advances in Difference Equations
Open Access
Explicit monotone iterative sequences for positive solutions of a fractional differential system with coupled integral boundary conditions on a half-line
by Haiyan Zhang, Yongqing Wang, Jiafa Xu
In this paper we consider a fractional differential system with coupled integral boundary value problems on a half-line, where the nonlinearity terms depend on unknown functions and the lower-order fractional derivative of unknown functions, and the fractional infinite boundary value conditions depend on the coupled infinite integral of unknown functions. By virtue of the monotone iterative technique, we find two explicit monotone iterative sequences which converge to the positive minimal and maximal solutions when the nonlinearities can satisfy certain nonlinear growth conditions.
Cited by 8
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Cited by 9
- 8 May 2020
- Published by Emerald Publishing in Journal of Chinese Economic and Foreign Trade Studies
Causes of U.S.-China trade imbalances: a review
by Yongqing Wang
Purpose: It is a common view to Trump administration and public that devaluation of Chinese currency is the origin of the US trade deficit. However, the previous literature does not support this common view. To better understand the causes of the US trade imbalances with China, this study aims to review the previous literature focusing on the causes of bilateral trade imbalances between the USA and China. Design/methodology/approach: Review previous literature according to the different reasons that each paper studies. Findings: Based on the previous literature, the Chinese exchange rate is not the main reason for the US trade imbalances. The official US trade figures overestimate the amount of deficit. The actual causes for the US trade deficit with China perhaps should be the relocation of production to China, low saving in the USA and high saving in China, and the US dollar as the international currency and reserve. Originality/value: By reviewing previous literature, the authors could better understand the puzzle of the US trade deficit with China.
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- 8 May 2020
- Published by Emerald Publishing in Journal of Chinese Economic and Foreign Trade Studies
Causes of U.S.-China trade imbalances: a review
by Yongqing Wang
Purpose: It is a common view to Trump administration and public that devaluation of Chinese currency is the origin of the US trade deficit. However, the previous literature does not support this common view. To better understand the causes of the US trade imbalances with China, this study aims to review the previous literature focusing on the causes of bilateral trade imbalances between the USA and China. Design/methodology/approach: Review previous literature according to the different reasons that each paper studies. Findings: Based on the previous literature, the Chinese exchange rate is not the main reason for the US trade imbalances. The official US trade figures overestimate the amount of deficit. The actual causes for the US trade deficit with China perhaps should be the relocation of production to China, low saving in the USA and high saving in China, and the US dollar as the international currency and reserve. Originality/value: By reviewing previous literature, the authors could better understand the puzzle of the US trade deficit with China.
Cited by 9
Open Access
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Cited by 2
- 21 March 2020
- Published by Wiley in Journal of Function Spaces
Existence and Nonexistence of Positive Solutions for High-Order Fractional Differential Equation Boundary Value Problems at Resonance
by Yongqing Wang, Huiqing Wang
We investigate positive solution for high-order fractional differential equations with resonant boundary value conditions. By using the spectral theory and the fixed point index theory, both the nonexistence and existence results of the resonant boundary value problems are given.
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- 21 March 2020
- Published by Wiley in Journal of Function Spaces
Open Access
Existence and Nonexistence of Positive Solutions for High-Order Fractional Differential Equation Boundary Value Problems at Resonance
by Yongqing Wang, Huiqing Wang
We investigate positive solution for high-order fractional differential equations with resonant boundary value conditions. By using the spectral theory and the fixed point index theory, both the nonexistence and existence results of the resonant boundary value problems are given.
Cited by 2
Open Access
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Cited by 19
- 21 February 2020
- Published by Springer Nature in Advances in Difference Equations
The Green’s function of a class of two-term fractional differential equation boundary value problem and its applications
by Yongqing Wang
In this paper, we consider a Riemann–Liouville type two-term fractional differential equation boundary value problem. Some positive properties of the Green’s function are deduced by using techniques of analysis. As application, we obtain the existence and multiplicity of positive solutions for a fractional boundary value problem under conditions that the nonlinearity $f(t,x)$ $f (t, x)$ may change sign and may be singular at $t = 0,1$ $t = 0, 1$ and $x=0$ $x = 0$ , and we also obtain the uniqueness results of positive solution for a singular problem by means of the monotone iterative technique.
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- 21 February 2020
- Published by Springer Nature in Advances in Difference Equations
Open Access
The Green’s function of a class of two-term fractional differential equation boundary value problem and its applications
by Yongqing Wang
In this paper, we consider a Riemann–Liouville type two-term fractional differential equation boundary value problem. Some positive properties of the Green’s function are deduced by using techniques of analysis. As application, we obtain the existence and multiplicity of positive solutions for a fractional boundary value problem under conditions that the nonlinearity $f(t,x)$ $f (t, x)$ may change sign and may be singular at $t = 0,1$ $t = 0, 1$ and $x=0$ $x = 0$ , and we also obtain the uniqueness results of positive solution for a singular problem by means of the monotone iterative technique.
Cited by 19

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