EXISTENCE OF EXTREMAL PERIODIC SOLUTIONS FOR NONLINEAR EVOLUTION INCLUSIONS

Nikolaos S. Papageorgiou and Nikolaos Yannakakis

Address. National Technical University, Department of Mathematics, Zografou Campus, Athens 157 80, GREECE

E-mail: npapg@math.ntua.gr

Abstract. We consider a nonlinear evolution inclusion defined in the abstract framework of an evolution triple of spaces and we look for extremal periodic solutions.                 The nonlinear operator is only pseudomonotone coercive. Our approach is based on techniques of multivalued analysis and on the theory of operators of                  monotone-type. An example of a parabolic distributed parameter system is also presented.

AMSclassification. 34G20, 35K55, 35R70

Keywords. Evolution triple, compact embedding,exremal solution, measurable multifunction, pseudomonotone map, Kadec-Klee property,
                   parabolic equation, $p$-Laplacian.