Mathematics Colloquia and Seminars
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Weighted L^2 cohomology of Coxeter groupsColloquium
|Speaker: ||Mike Davis, Ohio State University|
|Location: ||693 Kerr|
|Start time: ||Mon, Oct 18 2004, 4:10PM|
I will discuss a new type of cohomology, depending on a real
parameter q, of a cell complex associated to an infinite Coxeter group W.
As q varies these cohomology groups interpolate between ordinary
cohomology and cohomology with compact supports. Although these groups
are Hilbert spaces (usually infinite dimensional), they can be assigned a
"dimension" which is a nonnegative real number. These "dimensions" vary
continuously with the parameter q. When q is an integer, they give the L^2
Betti numbers of any regular building of type W and thickness q.