P. Mironescu et Vd. Radulescu, A MULTIPLICITY THEOREM FOR LOCALLY LIPSCHITZ PERIODIC FUNCTIONALS, Journal of mathematical analysis and applications, 195(3), 1995, pp. 621-637
We prove in this paper a multiplicity theorem of the Ljusternik-Schnir
elmann type for locally Lipschitz periodic funcitonals and related res
ults. The key argument in our proofs is Ekeland's variational principl
e and a non-smooth pseudo-gradient lemma. As an application of these a
bstract results we solve a non-linear set-valued elliptic problem. (C)
1995 Academic Press, Inc.