**Date & Time:** Friday, April 11, 2014, 15:30-17:30.

**Venue:** Room 216

**Title:** Second fundamental theorem for orthogonal groups

**Speaker:** Geetha Thangavelu, IMSc Chennai

**Abstract:** Let K be a field of characteristic zero. Let G denote the orthogonal group O(V, q) for a non-degenerate quadratic form q on a vector space V of dimension n over K. Brauer (1937) has proved that the natural map \phi from the Brauer algebra B_r(n) to the commutant of the O(V, q)-action on V^{\otimes r} is surjective. A recent paper of Lehrer and Zhang (2012) describes the kernel of this map. We will give an overview of this result of Lehrer and Zhang.