Electronic Journal of Differential Equations (Jun 2020)
Multiple solutions for mixed boundary value problems with phi-Laplacian operators
Abstract
Using Leray-Schauder degree theory and the method of upper and lower solutions we establish existence and multiplicity of solutions for problems of the form $$\displaylines{ (\phi(u'))' = f(t,u,u') \cr u(0)= u(T)=u'(0), }$$ where $\phi$ is an increasing homeomorphism such that $\phi(0)=0$, and f is a continuous function.