Solutions of Indefinite Hammerstein Equations

Consider the following equation:For positive definite or quasi-positive definite kernel k(x,y),the theory of equa-tion(1)has much been developed.But up to now,little is known about the caseof indefinite kernels.In this paper we get several results of the latter type. Let G R~N have finite measure and f(x,u)satisfy Caratheodory condition,