Nathalie Wahl (University of Oxford)
wahl@maths.ox.ac.uk
As double loop spaces are algebras over the framed discs operad, May's recognition principle seems to say that algebras over the little discs are algebras over the framed discs. We show that the extra structure coming for free doesn't in fact carry new information. We also relate the framed disks to a ribbon braid operad, and using the formalism of semidirect products, we describe its homology, the Batalin-Vilkovisky operad.