## University of Sydney Algebra Seminar

# Richard Hain (Duke University)

## Thursday 6th November, 12.05-12.55pm, Carslaw 159 ***NOTE UNUSUAL DAY***

### Algebraic completions of discrete and profinite groups

This talk will survey various algebric completions of discrete and profinite groups. Motivation from topology and algebraic/arithmetic geometry will be given for studying these completions. Examples from Galois theory and geometric topology (braid groups, mapping class groups, Torelli groups) will be given.