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Multiple constant sign and nodal solutions for nonlinear Neumann eigenvalue problems. (English) Zbl 1234.35169

Summary: We consider a nonlinear Neumann eigenvalue problem driven by a possibly nonhomogeneous differential operator which incorporates as a special case the \(p\)-Laplacian. We assume that the right-hand side nonlinearity is \(( p - 1)\)-superlinear, but need not satisfy the Ambrosetti-Rabinowitz condition or to be monotone. We show that, for all values of the parameter \(\lambda\) in an upper half line, the problem has two positive and two negative solutions. Subsequently, for the case of the \(p\)-Laplacian, we also produce a nodal solution. Finally, for the semilinear case we show that the problem has two nodal solutions.

MSC:

35P30 Nonlinear eigenvalue problems and nonlinear spectral theory for PDEs
35J92 Quasilinear elliptic equations with \(p\)-Laplacian
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