### Arcs as an effective model

**Kaufmann, R ***(Purdue University)*

Thursday 14 March 2013, 10:30-12:00

Seminar Room 2, Newton Institute Gatehouse

#### Abstract

The arc operad and its variations have proven itself in many instances to be a very clean minimal and explicit tool; for instance in giving models for the little discs, framed little discs, E_n operads, Sullivan PROP, etc on the topological level by basically the same formalism on surface. Furthermore, these models have a very nice cellular structure and hence are naturally suited to solve chain level conjectures. We will present some of these constructions and draw parallels to other activities at the program.