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Nathaniel Bottman, Institute for Advanced Study
Wednesday, February 13, 2019 - 3:30pm
PDL C-401
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I will explain my construction of the 2-associahedra, which are graded posets indexed by sequences of nonnegative integers. The 2-associahedra arose in symplectic geometry, where they control functoriality for a symplectic invariant called the Fukaya category. The elements of a 2-associahedron correspond to the degenerations in the compactified configuration space of marked points on vertical lines in R^2, up to translations and positive dilations. I will explain several properties of the 2-associahedra: they are abstract polytopes (in particular, they are thin and strongly connected); they are Eulerian (joint with my student Dylan Mavrides); and they have an operad-like structure that makes it possible to compute the face vectors using generating function techniques. Finally, I will present evidence for the conjecture that the 2-associahedra can be realized as convex polytopes. This will be a combinatorics talk; in particular, I will assume no symplectic background.

How I 'met' Dov Tamari by Jim Stasheff
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