论文部分内容阅读
Using fixedpoint index theory, we study the existence of positive solutions of the fourth order differential equation d4u/dt4 - g(t)F(t, u(t)) = 0 with some general boundary conditions, where g(t) is allowed to be singular at t = 0 and/or 1. Our results significantly extend and improve many known results even for non-singular cases. An example is given to show how to apply our theorems.