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Large forests and Littlewood

Nicolas Monod
(Ecolé Polytechnique Fédérale de Lausanne)
Fredag, 16 april, 2010, at 14:15-15:15, in Aud. D3 (1531-215)
Motivated by a classical result of Sz.-Nagy in functional analysis, Dixmier asked in 1950 which group representations can be made unitary. This question is still open, but I will report on some progress obtained with Epstein and Ozawa. We approach the question with ideas borrowed from XIXth century electricity theory as well as from contemporary percolation theory. As a result, we obtain notably non-unitarizable representations for Burnside groups and a new characterization of amenability. The talk will be expository.
Organiseret af: CTQM/QGM
Kontaktperson: Jørgen Ellegaard Andersen