Refined canonical stable Grothendieck polynomials and their duals

Abstract

In this paper we introduce refined canonical stable Grothendieck polynomials and their duals with two infinite sequences of parameters. These polynomials unify several generalizations of Grothendieck polynomials including canonical stable Grothendieck polynomials due to Yeliussizov, refined Grothendieck polynomials due to Chan and Pflueger, and refined dual Grothendieck polynomials due to Galashin, Liu, and Grinberg. We give Jacobi-Trudi-type formulas, combinatorial models, Schur expansions, Schur positivity, and dualities of these polynomials. We also consider flagged versions of Grothendieck polynomials and their duals with skew shapes.

Free fermions and Schur expansions of multi-Schur functions

“…By applying our free-fermionic presentation to these results, we (re)prove the Jacobi-Trudi formulas and Schur expansions for refined dual Grothendieck functions. These are seen as "fermionic" counterparts of the combinatorial/algebraic approaches concerning dual Grothendieck polynomials and their generalizations [5,16,18,19,21,22,24,25,26,27].…”