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The monomial expansions of modified Macdonald polynomials

Combinatorics 2025-07-08 v2 Mathematical Physics math.MP

Abstract

We discover a family AA of sixteen statistics on fillings of any given Young diagram and prove new combinatorial formulas for modified Macdonald polynomials, that is, H~λ(X;q,t)=σT(λ)xσqmaj(σ)tη(σ)\tilde{H}_{\lambda}(X;q,t)=\sum_{\sigma\in T(\lambda)}x^{\sigma}q^{maj(\sigma)}t^{\eta(\sigma)} for each statistic ηA\eta\in A. Building upon this new formula, we establish four compact formulas for the modified Macdonald polynomials, namely, H~λ(X;q,t)=σdε(σ)xσqmaj(σ)tη(σ)\tilde{H}_{\lambda}(X;q,t)=\sum_{\sigma}d_{\varepsilon}(\sigma)x^{\sigma}q^{maj(\sigma)}t^{\eta(\sigma)} which is summed over all canonical or dual canonical fillings of a Young diagram and dε(σ)d_{\varepsilon}(\sigma) is a product of tt-multinomials. Finally, the compact formulas enable us to derive four explicit expressions for the monomial expansion of modified Macdonald polynomials, one of which coincides with the formula given by Garbali and Wheeler (2020).

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Cite

@article{arxiv.2506.23373,
  title  = {The monomial expansions of modified Macdonald polynomials},
  author = {Emma Yu Jin and Xiaowei Lin},
  journal= {arXiv preprint arXiv:2506.23373},
  year   = {2025}
}

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45 Pages, 3 Figures