This colloquium has been postponed, to a later date, TBA. Colloquium

3:30 p.m., Friday

Math 100

## Professor Akbar Rhemtulla University of Alberta

### Residually Finite Groups

A group G is called Residually Finite if there is a set \{K_i ; \ i \in I \} of normal subgroups of G such that each K_i is of finite index in G and \cap K_i = 1. In other words, there is a system of homomorphisms \psi_{i} : \ G \rightarrow G_{i} , \ \ i \in I, where each G_i is finite and for each g \not= 1 in G, \psi_i(g) \not= 1 for some i. In many respects residually finite groups are well behaved and that is the theme of this talk.

Refreshments will be served in Math Annex Room 1115, 3:15 p.m.