Séminaire Lotharingien de Combinatoire, 91B.74 (2024), 12 pp.

Carmen Caprau, Nicolle González, Matthew Hogancamp and Mikhail Mazin

Triangular (q, t)-Schröder Polynomials and Khovanov-Rozansky Homology

Abstract. We define generalized Schröder polynomials Sλ(q,t,a) for triangular partitions and prove that these polynomials recover the triangular (q,t)-Catalan polynomials of [Forum Math. Pi 11 (2023), e5, 38 pp.] at a=0. Moreover, we show that the Poincaré polynomials of the reduced Khovanov-Rozansky homology of Coxeter knots of these partitions are given by Sλ(q,t,a). Finally, combined with recent results in [preprint, arχiv:2210.12569], we compute the Poincaré polynomial of the (d,dnm+1)-cable of the (n,m)-torus knot, thus proving a special case of the Oblomkov-Rassmusen-Shende conjecture for generic unibranched planar curves with two Puiseux pairs.


Received: November 15, 2023. Accepted: February 15, 2024. Final version: April 1, 2024.

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