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Department of Mathematics,
Department of Mathematics,
University of California San Diego
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Math 211A: Seminar in Algebra
Professor Nicolas Monod
EPFL
The fixed-point property and piecewise-projective transformations of the line
Abstract:
We describe a new and elementary proof of the fact that many groups of piecewise-projective transformation of the line are non-amenable by constructing an explicit action without fixed points. One the one hand, such groups provide explicit counter-examples to the Day-von Neumann problem. On the other hand, they illustrate that we can distinguish many "layers" of relative non-amenability between nested subgroups.
Adrian Ioana, Alireza Golsefidy
November 18, 2024
3:00 PM
APM 7321
Research Areas
Algebra Representation Theory****************************
