Three Nontrival Positive Solutions for Second Order Three PointBoundary Value Problems with Sign Changing Nonlinearities
具有变号非线性项的奇异二阶三点边值问题的三个非零正解

In this paper, the existence of multiple nontrival positive solutions for a class of singular second order three point boundary value problems with sign changing nonlinearities is investigated. Growth conditions are imposed on $f$, which yield the existence of at least three nontrival positive solutions by using the Leggett-Williams fixed point theorem.