En. Dancer et Zt. Zhang, Fucik spectrum, sign-changing, and multiple solutions for semilinear elliptic boundary value problems with resonance at infinity, J MATH ANAL, 250(2), 2000, pp. 449-464
In this paper, we use Fucik spectrum, ordinary differential equation theory
of Banach spaces to study semilinear elliptic boundary value problems with
jumping nonlinearities at zero or infinity, especially with resonance at i
nfinity, and obtain new results on the existence of multiple solutions and
sign-changing solutions with a weakening of the P.S. condition. In one case
we get up to seven nontrivial solutions. The techniques have independent i
nterest. (C) 2000 Academic Press.