{ "id": "2308.10100", "version": "v1", "published": "2023-08-19T20:13:08.000Z", "updated": "2023-08-19T20:13:08.000Z", "title": "Catalan numbers: from FC elements to classical diagram algebras", "authors": [ "Sadek Al Harbat" ], "categories": [ "math.CO", "math.RT" ], "abstract": "Let $W^c(A_n)$ be the set of fully commutative elements in the $A_n$-type Coxeter group. Using only the settings of their canonical form, we recount $W^c(A_n)$ by the definition of the Catalan numbers $C_{n+1}$ and find the Narayana numbers as well as the Catalan triangle. We determine the unique bijection between $W^c(A_n)$ and the set of non crossing diagrams that respects the monomial diagrammatical multiplication in the $A_n$-type Temperley-Lieb algebra.", "revisions": [ { "version": "v1", "updated": "2023-08-19T20:13:08.000Z" } ], "analyses": { "subjects": [ "05E10", "05Axx" ], "keywords": [ "classical diagram algebras", "catalan numbers", "fc elements", "type temperley-lieb algebra", "type coxeter group" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }