{ "id": "2104.11003", "version": "v1", "published": "2021-04-22T11:58:28.000Z", "updated": "2021-04-22T11:58:28.000Z", "title": "An explicit order matching for $L(3,n)$ from several approaches and its extension for $L(4,n)$", "authors": [ "Guoce Xin", "Yueming Zhong" ], "comment": "26 pages, 22 figures", "categories": [ "math.CO" ], "abstract": "Let $L(m,n)$ denote Young's lattice consisting of all partitions whose Young diagrams are contained in the $m\\times n$ rectangle. It is a well-known result that the poset $L(m,n)$ is rank symmetric, rank unimodal, and Sperner. A direct proof of this result by finding an explicit order matching of $L(m,n)$ is an outstanding open problem. In this paper, we present an explicit order matching $\\varphi$ for $L(3,n)$ by several different approaches, and give chain tableau version of $\\varphi$ that is very helpful in finding patterns. It is surprise that the greedy algorithm and a recursive knead process also give the same order matching. Our methods extend for $L(4,n)$.", "revisions": [ { "version": "v1", "updated": "2021-04-22T11:58:28.000Z" } ], "analyses": { "keywords": [ "explicit order matching", "approaches", "chain tableau version", "young diagrams", "well-known result" ], "note": { "typesetting": "TeX", "pages": 26, "language": "en", "license": "arXiv", "status": "editable" } } }