Let PΣn denote the group that can be thought of either as the group of motions of
the trivial n–component link or the group of symmetric automorphisms of a free
group of rank n. The integral cohomology ring of PΣn is determined, establishing a
conjecture of Brownstein and Lee.
Received: 16 October 2005
Revised: 6 February 2006
Accepted: 3 June 2006
Published: 11 July 2006
Proposed: Benson Farb
Seconded: Joan Birman, Walter Neumann