{ "id": "2405.14915", "version": "v1", "published": "2024-05-23T16:04:04.000Z", "updated": "2024-05-23T16:04:04.000Z", "title": "Cluster expansion formulas and perfect matchings for type B and C", "authors": [ "Azzurra Ciliberti" ], "comment": "22 pages. arXiv admin note: substantial text overlap with arXiv:2403.11308", "categories": [ "math.RT", "math.CO" ], "abstract": "Let $\\mathbf{P}_{2n+2}$ be the regular polygon with $2n+2$ vertices, and let $\\theta$ be the rotation of 180$^\\circ$. Fomin and Zelevinsky showed that $\\theta$-invariant triangulations of $\\mathbf{P}_{2n+2}$ are in bijection with the clusters of cluster algebras of type $B_n$ or $C_n$. Moreover, cluster variables correspond to the orbits of the action of $\\theta$ on the diagonals of $\\mathbf{P}_{2n+2}$. In this paper, we associate a labeled modified snake graph $\\mathcal{G}_{ab}$ to each $\\theta$-orbit $[a,b]$, and we get the cluster variables of type $B_n$ and $C_n$ which correspond to $[a,b]$ as perfect matching Laurent polynomials of $\\mathcal{G}_{ab}$. This extends the work of Musiker for cluster algebras of type B and C to every seed.", "revisions": [ { "version": "v1", "updated": "2024-05-23T16:04:04.000Z" } ], "analyses": { "keywords": [ "cluster expansion formulas", "cluster algebras", "perfect matching laurent polynomials", "cluster variables correspond", "regular polygon" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable" } } }