Set-valued tableaux rule for Lascoux polynomials

2021/10/01 by Yu, Tianyi
#Combinatorics (math.CO) #FOS: Mathematics

paper · doi:10.48550/arxiv.2110.00164

Abstract

Lascoux polynomials generalize Grassmannian stable Grothendieck polynomials and may be viewed as K-theoretic analogs of key polynomials. The latter two polynomials have combinatorial formulas involving tableaux: Lascoux and Schützenberger gave a combinatorial formula for key polynomials using right keys; Buch gave a set-valued tableau formula for Grassmannian stable Grothendieck polynomials. We establish a novel combinatorial rule for Lascoux polynomials involving right keys and set-valued tableaux. Our rule recovers the tableaux formulas of key polynomials and Grassmannian stable Grothendieck polynomials. To prove our rule, we construct a new abstract Kashiwara crystal structure on set-valued tableaux. This construction answers an open problem of Monical, Pechenik and Scrimshaw in the context of abstract Kashiwara crystal.

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