Stephen Simons - Böcker

This volume contains the proceedings of the workshop on Minimax Theory and Applications, held from September 30 to October 6, 1996, in Erice, Italy. The book deals mainly with classical minimax theory, reflecting on trends in the basic theory. In particular, the role of connectedness, which replaces that of convexity appearing in most classical results, is clearly emerging. The applications concern, among other things, game theory, integral functionals and monotone operators. This work should be of interest to graduate students and researchers involved in functional analysis, mathematical programming and optimization, general topology, operator theory and game theory.

In this new edition of LNM 1693 the essential idea is to reduce questions on monotone multifunctions to questions on convex functions. However, rather than using a “big convexification” of the graph of the multifunction and the “minimax technique”for proving the existence of linear functionals satisfying certain conditions, the Fitzpatrick function is used. The journey begins with a generalization of the Hahn-Banach theorem uniting classical functional analysis, minimax theory, Lagrange multiplier theory and convex analysis and culminates in a survey of current results on monotone multifunctions on a Banach space.The first two chapters are aimed at students interested in the development of the basic theorems of functional analysis, which leads painlessly to the theory of minimax theorems, convex Lagrange multiplier theory and convex analysis. The remaining five chapters are useful for those who wish to learn about the current research on monotone multifunctions on (possibly non reflexive) Banach space.

Focusing on the theory of monotone multifunctions on a Banach space, this work looks at the big convexification of a multi-function, convex functions associated with a multifunction, minimax theorems as a tool in functional analysis, and convex analysis. Topics include: results on the existence of continuous linear functionals; the conjugates, biconjugates and subdifferentials of convex lower semicontinuous functions; Fenchel duality; positive linear operators from a Banach space into its dual; the sum of maximal monotone operators; and a list of open problems. The reader is expected to know basic functional analysis and calculus of variations, including the Bahn-Banach theorem, Banach-Alaoglu theorem, and Ekeland's variational principle.