# A generalization of $(q,t)$-Catalan and nabla operators

Abstract : We introduce non-commutative analogs of $k$-Schur functions and prove that their images by the non-commutative nabla operator $\blacktriangledown$ is ribbon Schur positive, up to a global sign. Inspired by these results, we define new filtrations of the usual $(q,t)$-Catalan polynomials by computing the image of certain commutative $k$-Schur functions by the commutative nabla operator $\nabla$. In some particular cases, we give a combinatorial interpretation of these polynomials in terms of nested quantum Dick paths.
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Cited literature [19 references]

https://hal.inria.fr/hal-01185130
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• HAL Id : hal-01185130, version 1

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N. Bergeron, F. Descouens, M. Zabrocki. A generalization of $(q,t)$-Catalan and nabla operators. 20th Annual International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC 2008), 2008, Viña del Mar, Chile. pp.513-528. ⟨hal-01185130⟩

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