RECENT DEVELOPMENTS IN DYNAMICAL SYSTEMS: THREE PERSPECTIVES F. BALIBREA Universidad de Murcia, Dpto. de Matem´aticas, 30100-Murcia, Spain E-mail:
[email protected] T. CARABALLO Universidad de Sevilla, Dpto. Ecuaciones Diferenciales y An´alisis Num´erico, Apdo. de Correos 1160, 41080-Sevilla (Spain) E-mail:
[email protected] P.E. KLOEDEN Institut f¨ur Mathematik, Goethe-Universit¨at, D-60054 Frankfurt am Main, Germany E-mail:
[email protected] J. VALERO Univ. Miguel Hern´andez de Elche, Centro de Investigaci´on Operativa, Avda. Universidad s/n, 03202 Elche (Alicante), Spain E-mail:
[email protected] Received September 15, 2009; Revised October 30, 2009 Dedicated to the memory of Valery S. Melnik The aim of this paper is to give an account of some problems considered in past years in the setting of Dynamical Systems, some new research directions and also state some open problems Keywords: Topological entropy, Li-Yorke chaos, Lyapunov exponent, continua, non- autonomous systems, difference equations, ordinary and partial differential equations, set-valued dynamical system, global attractor, non-autonomous and random pullback attractors. Mathematics Subject Classifications (2000): 35B40, 35B41, 35K40, 35K55, 37B25, 37B30, 37B40, 37B45, 37B55, 37E05, 37E15, 39A20 58C06, 60H15. 1. Introduction nected with celestial mechanics. In particular, the theory of discrete dynamical systems, which mainly uses iteration theory, is one of the most relevant The theory of dynamical systems has a long prehis- topics in the subject. tory, but essentially started in its present form with the work of Poincar´eand Birkhoff on problems con- The purpose of this tutorial is to give a par- 1 2 Balibrea, Caraballo, Kloeden & Valero tial account of the progress obtained in discrete and centers and depth of centers [Ye, 1993, Kato, 1995, continuous systems is recent years, to present some Kato, 1998, Efremova & Makhrova, 2003] on open and new problems.