Study On Solvability Of A Class Of Fourth-order Ordinary Differential Equation With Periodic Boundary Conditions

In this thesis,by using Mawhin's coincidence degree theorem,we consider solv-ability for nonlinear fourth-order periodic boundary value problem with indefinite weightwhere ?>0 is sufficiently large,a:R?R is a locally integrable T-periodic function,and allowed to change sign,g:R?R is continuous,and satisfying(?)...