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Fixed points for Kakutani factorizable multifunctions
Lassonde M.
Journal of Mathematical Analysis and applications 152, 1 (1990) 46-60 - http://hal.archives-ouvertes.fr/hal-00699225
Marc Lassonde ()1
1 :  LAMIA - Laboratoire de Mathématiques Informatique et Applications
Université des Antilles et de la Guyane
Campus de Fouillole BP250 97159 Pointe à Pitre
France
Mathématiques/Analyse fonctionnelle
Fixed points for Kakutani factorizable multifunctions
A multifunction Γ is called a Kakutani multifunction if there exist two nonempty convex sets X and Y , each in a Hausdorff topological vector space, such that Γ : X → Y is upper semi-continuous with nonempty compact convex values. We prove the following extension of the Kakutani fixed point theorem : Let Γ : X → X be a multi-function from a simplex X into itself ; if Γ can be factorized by an arbitrary finite number of Kakutani multifunctions, then Γ has a fixed point. The proof relies on a simplicial approximation technique and the Brouwer fixed point theorem. Extensions to infinite-dimensional spaces and applications to game theory are given.
Anglais

Journal of Mathematical Analysis and applications
internationale
1990
152
1
46-60