Yongkun Li
Yunnan University
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Featured researches published by Yongkun Li.
Boundary Value Problems | 2011
Yongkun Li; Jiangye Shu
In this paper, we first present a class of first-order nonlinear impulsive integral boundary value problems on time scales. Then, using the well-known Guo-Krasnoselskii fixed point theorem and Legget-Williams fixed point theorem, some criteria for the existence of at least one, two, and three positive solutions are established for the problem under consideration, respectively. Finally, examples are presented to illustrate the main results.MSC: 34B10; 34B37; 34N05.
Boundary Value Problems | 2011
Yongkun Li; Tianwei Zhang
We are concerned with the following second-order -Laplacian dynamic equations on time scales , , with integral boundary conditions , . By using Legget-Williams fixed point theorem, some criteria for the existence of at least three positive solutions are established. An example is presented to illustrate the main result.
Advances in Mathematical Physics | 2016
Yanning Wang; Jianwen Zhou; Yongkun Li
Using conformable fractional calculus on time scales, we first introduce fractional Sobolev spaces on time scales, characterize them, and define weak conformable fractional derivatives. Second, we prove the equivalence of some norms in the introduced spaces and derive their completeness, reflexivity, uniform convexity, and compactness of some imbeddings, which can be regarded as a novelty item. Then, as an application, we present a recent approach via variational methods and critical point theory to obtain the existence of solutions for a -Laplacian conformable fractional differential equation boundary value problem on time scale , , , where denotes the conformable fractional derivative of of order at , is the forward jump operator, , and . By establishing a proper variational setting, we obtain three existence results. Finally, we present two examples to illustrate the feasibility and effectiveness of the existence results.
Boundary Value Problems | 2012
Jianwen Zhou; Yanning Wang; Yongkun Li
AbstractIn this paper, we present a recent approach via variational methods and critical point theory to obtain the existence of solutions for the nonautonomous second-order system on time scales with impulsive effectsn {uΔ2(t)+A(σ(t))u(σ(t))+∇F(σ(t),u(σ(t)))=0,Δ-a.e.xa0t∈[0,T]Tκ;u(0)−u(T)=uΔ(0)−uΔ(T)=0,(ui)Δ(tj+)−(ui)Δ(tj−)=Iij(ui(tj)),i=1,2,…,N,j=1,2,…,p,n where t0=0<t1<t2<⋯<tp<tp+1=T, tj∈[0,T]T (j=0,1,2,…,p+1), u(t)=(u1(t),u2(t),…,uN(t))∈RN, A(t)=[dlm(t)] is a symmetric N×N matrix-valued function defined on [0,T]T with dlm∈L∞([0,T]T,R) for all l,m=1,2,…,N, Iij:R→R (i=1,2,…,N, j=1,2,…,p) are continuous and F:[0,T]T×RN→R. Finally, two examples are presented to illustrate the feasibility and effectiveness of our results.MSC:34B37, 34N05.
Boundary Value Problems | 2011
Yongkun Li; Yanshou Dong
In this article, we investigate the multiplicity of positive solutions for a fourth-order system of integral boundary value problem on time scales. The existence of multiple positive solutions for the system is obtained by using the fixed point theorem of cone expansion and compression type due to Krasnoselskill. To demonstrate the applications of our results, an example is also given in the article.
Boundary Value Problems | 2007
Yongkun Li; Hongtao Zhang
We consider the existence of minimal and maximal solutions of periodic boundary value problems for first-order impulsive integrodifferential equations of mixed-type on time scales by establishing a comparison result and using the monotone iterative technique.
Boundary Value Problems | 2011
Yongkun Li; Tianwei Zhang
Using the variational principle of Ricceri and a local mountain pass lemma, we study the existence of three distinct solutions for the following resonant Duffing-type equations with damping and perturbed term , a.e. , and without perturbed term , a.e. , .
Bulletin of the Malaysian Mathematical Sciences Society | 2017
Jianwen Zhou; Yongkun Li; Yanning Wang
Mediterranean Journal of Mathematics | 2016
Yanning Wang; Yongkun Li; Jianwen Zhou
Taiwanese Journal of Mathematics | 2013
Jianwen Zhou; Yongkun Li; Yanning Wang