Jesse Kim

I am co-organizing the Combinatorics Seminar along with Zach Hamaker.

It meets Tuesdays P8 (3:00-3:50) in LIT 225.

Date	Speaker	Title	Abstract
9/3	Jesse Kim	Webs for Flamingoes	Webs are certain planar graphs whose combinatorics can help illuminate the invariant theory of SL_r and the structure of rectangular Specht modules; the simplest family of webs consists of noncrossing perfect matchings. This talk will include an introduction to the theory of webs and show how to modify webs to also obtain the not-quite-rectangular "flamingo" Specht modules, so called because they appear to stand on one leg.
9/10
9/17
9/24	Vincent Holmlund	Totally symmetric self-complementary plane partition matrices: enumerative properties and polytopes	Plane partitions in the totally symmetric self-complementary symmetry class(TSSCPP) are known to be equinumerous with n x n alternating sign matrics, but no explicit bijection is known. In this talk, I will discuss a set of {0,1,-1}-matrices, called Magog matrices, which are in bijection with TSSCPP. I will explore their enumerative properties and compare them to those of ASMs. I will also look at them from a geometric perspective by discussing two different polytopes that are formed from TSSCPP.
10/1	Jack Chou	Constructing maximal pipedreams of double Grothendieck polynomials	Pipedreams are combinatorial objects that compute polynomials labeled by permutations in Schubert calculus. Pechenik, Speyer and Weigandt defined a statistic rajcode() on permutations which characterizes the leading monomial in top degree components of double Grothendieck polynomials. Their proof is combinatorial:  They showed there exists a unique pipedream of a permutation w with row weight rajcode(w) and column weight rajcode(w^{-1}). They proposed the problem of finding a direct recipe for this pipedream. We solve this problem by providing an algorithm that constructs this pipedream via ladder moves. This is joint work with Tianyi Yu.
10/8
10/15
10/22
10/29
11/5
11/12
11/19
12/3