Abstract
We show that many of the results obtained for the Landesman-Lazer type problems can be extended to operators having unbounded essential spectra stretching from negative to positive infinity. The only requirement is that they have an isolated eigenvalue of finite multiplicity.
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Reference24 articles.
1. S. Ahmed, A. C. Lazer, J. Paul; Elementary critical point theory and perturbations of elliptic boundary value problems at resonance, Indiana Univ. Math. J., 25 (1976), 933-944.
2. A. Ambrosetti, G. Mancini; Existence and multiplicity results for nonlinear elliptic problems with linear part at resonance, J. Diff. Eq., 28 (1978), 220-245.
3. A. Ambrosetti, G. Mancini; Theorems of existence and multiplicity for nonlinear elliptic problems with noninvertible linear part, Ann. Scuola Norm. Sup. Pisa, 5 (1978), 15-28.
4. P. Bartolo, V. Benci, D. Fortunato; Abstract critical point theorems and applications to some nonlinear problems with “strong” resonance at infinity, Nonlinear Anal. TMA, 7 (1983), 981-1012.
5. H. Brezis, L. Nirenberg; Characterizations of the ranges of some nonlinear operators and applications boundary value problems, Ann. Scoula Norm. Sup. Pisa 5 (1978), 225-326.