Algebraic & Enumerative Combinatorics - Santiago Estupiñán

Thursday, February 12, 2026 2:30 pm - 3:30 pm EST (GMT -05:00)

Title: Jeu de Taquin for Mixed Insertion and a Problem of Soojin Cho

Speaker: Santiago Estupiñán
Affiliation: University of Waterloo
Location: MC 5417

Abstract: 

Serrano (2010) introduced the shifted plactic monoid, governing Haiman's (1989) mixed insertion algorithm, as a type B analogue of the classical plactic monoid that connects jeu de taquin of Young tableaux with the Robinson–Schensted–Knuth insertion algorithm. Serrano proposed a corresponding definition of skew shifted plactic Schur functions. Cho (2013) disproved Serrano's conjecture regarding this definition, by showing that the functions do not live in the desired ring and hence cannot provide an algebraic interpretation of tableau rectification or of the corresponding structure coefficients. Cho asked for a new definition with particular properties. We introduce such a definition and prove that it behaves as desired. We also introduce the first jeu de taquin theory that computes mixed insertion. This is joint work with Oliver Pechenik.

There will be a pre-seminar presenting relevant background at the beginning graduate level starting at 1:30pm in MC 5417.