{ "id": "1611.01251", "version": "v1", "published": "2016-11-04T02:51:43.000Z", "updated": "2016-11-04T02:51:43.000Z", "title": "Ordered set partitions and the 0-Hecke algebra", "authors": [ "Jia Huang", "Brendon Rhoades" ], "comment": "30 pages", "categories": [ "math.CO" ], "abstract": "Let the symmetric group $\\mathfrak{S}_n$ act on the polynomial ring $\\mathbb{Q}[\\mathbf{x}_n] = \\mathbb{Q}[x_1, \\dots, x_n]$ by variable permutation. The coinvariant algebra is the graded $\\mathfrak{S}_n$-module $R_n := {\\mathbb{Q}[\\mathbf{x}_n]} / {I_n}$, where $I_n$ is the ideal in $\\mathbb{Q}[\\mathbf{x}_n]$ generated by invariant polynomials with vanishing constant term. Haglund, Rhoades, and Shimozono introduced a new quotient $R_{n,k}$ of the polynomial ring $\\mathbb{Q}[\\mathbf{x}_n]$ depending on two positive integers $k \\leq n$ which reduces to the classical coinvariant algebra of the symmetric group $\\mathfrak{S}_n$ when $k = n$. The quotient $R_{n,k}$ carries the structure of a graded $\\mathfrak{S}_n$-module; Haglund et. al. determine its graded isomorphism type and relate it to the Delta Conjecture in the theory of Macdonald polynomials. We introduce and study a related quotient $S_{n,k}$ of $\\mathbb{F}[\\mathbf{x}_n]$ which carries a graded action of the 0-Hecke algebra $H_n(0)$, where $\\mathbb{F}$ is an arbitrary field. We prove 0-Hecke analogs of the results of Haglund, Rhoades, and Shimozono. In the classical case $k = n$, we recover earlier results of Huang concerning the 0-Hecke action on the coinvariant algebra.", "revisions": [ { "version": "v1", "updated": "2016-11-04T02:51:43.000Z" } ], "analyses": { "keywords": [ "ordered set partitions", "symmetric group", "invariant polynomials", "vanishing constant term", "polynomial ring" ], "note": { "typesetting": "TeX", "pages": 30, "language": "en", "license": "arXiv", "status": "editable" } } }