Periodic solutions to differential systems with unbounded or periodic nonlinearities. (English) Zbl 1109.34032

The authors investigate the existence and multiplicity of periodic solutions to differential systems of Josephson type. They prove some variants of results obtained by K. C. Chang and others [see also A. Fonda and J. Mawhin, in: M. Themistocles Rassias (ed.), The Problem of Plateau: A tribute to J. Douglas and T. Rado. London: World Scientific Publishing Co. Pte. Ltd, 111–128 (1992; Zbl 0798.58028)]. The proofs use variational methods, and in particular the saddle point theorem with some of its generalizations.


34C25 Periodic solutions to ordinary differential equations


Zbl 0798.58028
Full Text: DOI


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