Existence results for some Kirchhoff-Carrier problems

Analyzing the viscoelastic problem for small vibrations of elastic strings, Kirchhoff and Carrier proposed two different models of nonlinear partial differential equations. By combining these two models, we deal here with some nonlocal hyperbolic problems that cover a large class of Kirchhoff and Carrier type problems. The existence of local solutions of degenerate problems as well as local and nonlocal solutions of nondegenerate problems is established. The proofs are based on the combination of the Schauder fixed point theorem with some asymptotic method.     

Existence results for some quasilinear parabolic problems

We first give an existence theorem, for some equations associated with Leray-Lions operators, assuming the existence of a subsolution smaller than a supersolution. Then we prove, with an additional hypothesis on the operator, that in the previous theorem, we can replace the subsolution by two subsolutions and the supersolution by two supersolutions. Finally, we deduce the existence of a smallest and a greatest solution.     

Existence of solutions for some higher order boundary value problems

In this paper, we are concerned with the existence of solutions for the higher order boundary value problem in the form

     

Existence results for some polyharmonic problems in the half-space

We study the existence of positive solutions of the m-polyharmonic nonlinear elliptic equation m(−Δ)u+f(⋅,u)=0 in the half-space , n?2 and m?1. Our purpose is to give two existence results for the above equation subject to some boundary conditions, where the nonlinear term f(x,t) satisfies some appropriate conditions related to a certain Kato class of functions .     

Existence and multiplicity results for nonlinear periodic boundary value problems

This paper studies the existence of positive solutions for periodic boundary value problems. The criteria for the existence, nonexistence and multiplicity of positive solutions are established by using the Global continuation theorem, fixed point index theory and approximate method. The results obtained herein generalize and complement some previous findings of [J.R. Graef, L. Kong, H. Wang, Existence, multiplicity, and dependence on a parameter for a periodic boundary value problem, J. Differential Equations 245 (2008) 1185–1197] and some other known results.     

Existence results for second-order impulsive boundary value problems on time scales

In this paper, using a fixed point theorem due to Krasnoselskii and Zabreiko and the Leggett–Williams fixed point theorem respectively, we investigate the existence of one solution and three nonnegative solutions to second-order impulsive equations on time scales.     

On some third order nonlinear boundary value problems: Existence, location and multiplicity results

We prove an Ambrosetti-Prodi type result for the third order fully nonlinear equation

u^?(t)+f(t,u(t),u^′(t),u^″(t))=sp(t)     

Existence of sign-changing solutions for some asymptotically linear three-point boundary value problems

In this paper, by using the topological degree theory and the fixed point index theory, the existence of three kinds of solutions (i.e., sign-changing solutions, positive solutions and negative solutions) for asymptotically linear three-point boundary value problems is obtained.     

Existence of solutions for some discrete boundary value problems with a parameter

In this paper, the existence and multiplicity results of solutions are obtained for the discrete nonlinear two point boundary value problem (BVP) ; u(0)=0=Δu(T), where T is a positive integer, Z(1,T)={1,2,…,T}, Δ is the forward difference operator defined by Δu(k)=u(k+1)-u(k) and f:Z(1,T)×R→R is continuous, λ∈R⁺ is a parameter. By using the critical point theory and Morse theory, we obtain that the above (BVP) has solutions for λ being in some different intervals.     

Existence and iterative method for some fourth order nonlinear boundary value problems

This work is devoted to proving the existence of the iterative solution to a fourth order boundary value problem. By the use of a novel efficient method for nonlinear fourth order boundary value problem, the existence and uniqueness of solution for the problem is obtained. The monotony of iterations is also considered. Some examples are presented to illustrate the main results.     

Existence of three positive solutions for some second-order m-point boundary value problems

By using fixed-point theorems, some new results for multiplicity of positive solutions for some second order m-point boundary value problems are obtained.The associated Green＇s function of these problems are also given.