A combinatorial approach to the \(q,t\)-symmetry relation in Macdonald polynomials. (English) Zbl 1337.05109

Gillespie, Maria Monks

Electron. J. Comb. 23, No. 2, Research Paper P2.38, 64 p. (2016).

Summary: Using the combinatorial formula for the transformed Macdonald polynomials of J. Haglund et al. [J. Am. Math. Soc. 18, No. 3, 735–761 (2005; Zbl 1061.05101)], we investigate the combinatorics of the symmetry relation \(\widetilde{H}_\mu(\mathbf{x};q,t)=\widetilde{H}_{\mu^{\ast}}(\mathbf{x};t,q)\). We provide a purely combinatorial proof of the relation in the case of Hall-Littlewood polynomials (\(q=0\)) when \(\mu\) is a partition with at most three rows, and for the coefficients of the square-free monomials in \(\mathbf{x}\) for all shapes \(\mu\). We also provide a proof for the full relation in the case when \(\mu\) is a hook shape, and for all shapes at the specialization \(t=1\). Our work in the Hall-Littlewood case reveals a new recursive structure for the cocharge statistic on words.

MSC:

05E10	Combinatorial aspects of representation theory
05E05	Symmetric functions and generalizations
33D52	Basic orthogonal polynomials and functions associated with root systems (Macdonald polynomials, etc.)

Keywords:

Macdonald polynomials; Hall-Littlewood polynomials; Young tableaux; cocharge; Garsia-Procesi modules; Mahonian statistics