Positive solutions for some beam equation boundary value problems.
Values of are determined for which there exist positive solutions of the system of three-point boundary value problems, , , for , and satisfying, , , , . A Guo-Krasnosel’skii fixed point theorem is applied.
We study a third order singular boundary value problem with multi-point boundary conditions. Sufficient conditions are obtained for the existence of positive solutions of the problem. Recent results in the literature are significantly extended and improved. Our analysis is mainly based on a nonlinear alternative of Leray-Schauder.
We study the existence of positive solutions to the fourth-order two-point boundary value problem where is a Riemann-Stieltjes integral with being a nondecreasing function of bounded variation and . The sufficient conditions obtained are new and easy to apply. Their approach is based on Krasnoselskii’s fixed point theorem and the Avery-Peterson fixed point theorem.