G. Infante, J. Webb
Aug 1, 2002
Journal of Mathematical Analysis and Applications
Using the theory of fixed point index, we establish new results for the existence of nonzero solutions of integral equations of the form u(t)=∫Gk(t,s)f(s,u(s))ds, where G is a compact set in Rn and k changes sign, so positive solutions may not exist, f satisfies Caratheodory conditions and k may be discontinuous. We apply our results to prove the existence of nontrivial solutions of some nonlocal boundary value problems.