The volume, devoted to variational analysis and its applications,
collects selected and refereed contributions, which provide an outline
of the field. The meeting of the title "Equilibrium Problems and
Variational Models", which was held in Erice (Sicily) in the period June
23 - July 2 2000, was the occasion of the presentation of some of these
papers; other results are a consequence of a fruitful and constructive
atmosphere created during the meeting. New results, which enlarge the
field of application of variational analysis, are presented in the book;
they deal with the vectorial analysis, time dependent variational
analysis, exact penalization, high order deriva- tives, geometric
aspects, distance functions and log-quadratic proximal methodology. The
new theoretical results allow one to improve in a remarkable way the
study of significant problems arising from the applied sciences, as
continuum model of transportation, unilateral problems, multicriteria
spatial price models, network equilibrium problems and many others. As
noted in the previous book "Equilibrium Problems: Nonsmooth Optimization
and Variational Inequality Models", edited by F. Giannessi, A. Maugeri
and P.M. Pardalos, Kluwer Academic Publishers, Vol. 58 (2001), the
progress obtained by variational analysis has permitted to han- dle
problems whose equilibrium conditions are not obtained by the mini-
mization of a functional. These problems obey a more realistic
equilibrium condition expressed by a generalized orthogonality
(complementarity) con- dition, which enriches our knowledge of the
equilibrium behaviour. Also this volume presents important examples of
this formulation.