Skip to main content
5 events
when toggle format what by license comment
Jul 18, 2010 at 23:45 comment added Kevin Walker Maybe I shouldn't have said "characterize mapping class groups" in the original answer. The Hatcher-Thurston 2-complex was used to derive a presentation of the MCG, but for the TQFT application you need the 2-complex, not the presentation of the MCG.
Jul 18, 2010 at 23:43 comment added Kevin Walker Sure. Hatcher and Thurston constructed a simply connected 2-complex for a surface Y, with vertices the pants decompositions of Y, edges "F" and "S" moves between pants decompositions, and some 2-cells (see math.cornell.edu/~hatcher/Papers/pantsdecomp.pdf). The Moore-Seiberg equations correspond to the Hatcher-Thurston 2-cells, or rather to lifts of those 2-cells to a similar 2-complex for pants decompositions "with seams". By "Hatcher-Thurston for 3-manifolds" I meant doing this when Y is a 3-manifold, maybe with vertices corresponding to compression-body decomps of Y.
Jul 18, 2010 at 22:19 comment added Ian Agol hey Kevin, Can you expand upon what you mean by your last sentence (Hatcher-Thurston for 3-manifolds)?
Jul 11, 2010 at 2:06 vote accept Theo Johnson-Freyd
Jul 9, 2010 at 13:14 history answered Kevin Walker CC BY-SA 2.5