# Recent and upcoming talks by Jan Pachl

## Jan Pachl: Topological centres for group actions

Place: Fields Institute (Room 210) Date: December 1, 2017 (13:30-15:00) Speaker: Jan Pachl Title: Topological centres for group actions Abstract: Based on joint work with Matthias Neufang and Juris Steprans. By a variant of Foreman’s 1994 construction, every tower ultrafilter on $\omega$ is the unique invariant mean for an amenable subgroup of $S_\infty$, the infinite symmetric group. continue reading…

## Jan Pachl: One-point DTC sets for convolution semigroups

29/November/2013, 14:00–15:00 Fields institute, Room 210 Speaker:  Jan Pachl Title:  One-point DTC sets for convolution semigroups  Abstract: Every topological group G naturally embeds in the Banach algebra LUC(G)*. The topological centre of LUC(G)* is defined to be the set of its elements for which the left multiplication is w*–w*-continuous. continue reading…

## Jan Pachl: Measurable centres in convolution semigroups

Toronto Set Theory Seminar Friday, January 13 (next week) from 1:30-3pm Fields, Room 210 Speaker: Jan Pachl (Fields) Title: Measurable centres in convolution semigroups Abstract: Every topological group G naturally embeds in larger spaces, algebraically and topologically. continue reading…