DTC ultrafilters on groups
Speaker:
Jan Pachl
Date and Time:
Friday, November 15, 2019 - 1:30pm to 2:30pm
Location:
Fields Institute, Room 210
Abstract:
An infinite finitely generated group G is virtually abelian if and only if it does not admit a DTC ultrafilter = an ultrafilter that determines the topological centre of the semigroup βG. More generally, we have necessary conditions and, for countable groups, sufficient conditions for the existence of DTC ultrafilters. This is joint work with Juris Steprans.