Type B extensions of Cauchy identity and Schur-positivity related to Chow’s quasisymmetric functions.
Time: 15:00 -- Location: Salle Philippe Flajolet du LIX
The Cauchy identity is a fundamental formula in algebraic combinatorics that captures all the nice properties of the RSK correspondence. In particular, expanding both sides of the identity with Gessel's quasisymmetric functions allows to recover the descent preserving property, an essential tool to prove the Schur positivity of sets of permutations. We introduce a new type B extension of Schur-positivity based on Chow's quasisymmetric functions and domino functions, i.e. generating functions for domino tableaux. Further, we suggest a q-analogue of the modified domino functions to extend a type B Cauchy identity by Lam and link it with Chow's quasisymmetric functions. We apply this result to a new framework of type B q-Schur positivity and to prove new equidistribution results for some sets of domino tableaux.