Orderable groups and 3-manifolds
Abstract: This course will begin with an introduction to left-orderable and circularly orderable groups, and will focus on establishing the tools needed to tackle the problem of left-ordering fundamental groups of 3-manifolds–such as the Burns-Hale theorem, actions on R and S^1, and related Euler class arguments. With these tools in hand, we’ll move on to investigating some of the exceptional behaviour of left-orderability with respect to fundamental groups of 3-manifolds. Our chosen examples will draw inspiration from the L-space conjecture, with a focus on manifolds arising from Dehn surgery, and on Seifert fibred spaces. We’ll also encounter several open problems along the way, some completely algebraic having only to do with orderable groups, and others that are linked to special cases of the L-space conjecture.