Electronic Journal of Qualitative Theory of Differential Equations (Oct 2017)
Resonant semilinear Robin problems with a general potential
Abstract
We consider a semilinear Robin problem driven by the Laplacian plus an indefinite and unbounded potential. The reaction term is a Carath\'eodory function which is resonant with respect to any nonprincipal eigenvalue both at $\pm \infty$ and 0. Using a variant of the reduction method, we show that the problem has at least two nontrivial smooth solutions.
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