Algebra Seminar

Apart from the symmetric group on 6 letters, I don't know of any Coxeter group that has an interesting outer automorphism. In this talk I shall survey what I know about outer automorphisms of Coxeter groups, and outline a proof of the following fact: if W is an infinite rank 3 Coxeter group whose Coxeter graph contains no infinite bonds then the automorphism group of W is generated by graph automorphisms and inner automorphisms.