Essential dimensions of algebraic groups

Given an algebraic group G over a field K one can associate to it the set of isomorphism classes of G-torsors. The essential dimension ed(G) of G is a discrete invariant which measures how complicated G-torsors are. In general it is difficult to compute ed(G). In the talk we give a survey of results related to computation of essential dimensions through orthogonal representations.

Refreshments will be served at 2:45 p.m. (MATX 1115, Math Faculty Lounge).