Séminaire Lotharingien de Combinatoire, 93B.21 (2025), 12 pp.

Samuel Spellman and Cristian Lenart

A Combinatorial Model for Affine Demazure Crystals of Levels Zero and One

Abstract. Certain affine crystals, known as Kirillov-Reshetikhin (KR) crystals, were realized in a uniform way (for all untwisted affine types) in terms of the quantum alcove model, and their graded characters were shown to coincide with the specialization of symmetric Macdonald polynomials at t=0. We generalize these results by introducing a "non-symmetric" quantum alcove model for certain level zero Demazure-type crystals inside tensor products of KR crystals, whose graded characters coincide with non-symmetric Macdonald polynomials at t=0. Moreover, in type A, we construct an explicit affine crystal isomorphism between the non-symmetric quantum alcove model and the semi-standard key tabloid model for level one affine Demazure crystals due to Assaf and Gonzáe;lez.


Received: November 15, 2024. Accepted: February 15, 2025. Final version: April 1, 2025.

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