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arXiv · 1602.05153

Non-symmetric Macdonald polynomials and Demazure-Lusztig operators

Per Alexandersson
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Abstract

We extend the family non-symmetric Macdonald polynomials and define general-basement Macdonald polynomials. We show that these also satisfy a triangularity property with respect to the monomials bases and behave well under the Demazure-Lusztig operators. The symmetric Macdonald polynomials $J_\lambda$ are expressed as a sum of general-basement Macdonald polynomials via an explicit formula. By letting $q=0$, we obtain $t$-deformations of key polynomials and Demazure atoms and we show that the Hall--Littlewood polynomials expand positively into these. This generalizes a result by Haglund, Luoto, Mason and van Willigenburg. As a corollary, we prove that Schur polynomials decompose with non-negative coefficients into $t$-deformations of general Demazure atoms and thus generalizing the $t=0$ case which was previously known. This gives a unified formula for the classical expansion of Schur polynomials in Hall-Littlewood polynomials and the expansion of Schur polynomials into Demazure atoms.

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Per Alexandersson. 2016-02-16. Non-symmetric Macdonald polynomials and Demazure-Lusztig operators. https://arxiv.org/abs/1602.05153

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