Mathematics Colloquium
Speaker: Andrzej Zuk (Paris 7)
Title: On a problem of Atiyah
Time: Monday, January 16, 3:30 pm
Place: Amado 232, Technion
Colloquium homepage:  <>
Abstract: In 1976, Michael Atiyah defined L2-Betti numbers for manifolds and
asked a question about their rationality. These numbers arise as the
von Neumann dimensions of kernels of certain operators acting on the
L2-space of the fundamental group of a manifold. The problem
concerning their values is closely related to the Kaplansky
zero-divisor question. We present constructions of closed manifolds
with irrational L2-Betti numbers.
Technion Math. Net (TECHMATH)
Editor: Michael Cwikel   <> 
Announcement from: Amir Yehudayoff   <>