{ "id": "0810.3638", "version": "v1", "published": "2008-10-20T19:10:57.000Z", "updated": "2008-10-20T19:10:57.000Z", "title": "Cluster expansion formulas and perfect matchings", "authors": [ "Gregg Musiker", "Ralf Schiffler" ], "comment": "19 pages, 8 figures", "categories": [ "math.RT", "math.CO" ], "abstract": "We study cluster algebras with principal coefficient systems that are associated to unpunctured surfaces. We give a direct formula for the Laurent polynomial expansion of cluster variables in these cluster algebras in terms of perfect matchings of a certain graph $G_{T,\\gamma}$ that is constructed from the surface by recursive glueing of elementary pieces that we call tiles. We also give a second formula for these Laurent polynomial expansions in terms of subgraphs of the graph $G_{T,\\gamma}$.", "revisions": [ { "version": "v1", "updated": "2008-10-20T19:10:57.000Z" } ], "analyses": { "subjects": [ "16S99", "05E99", "05C70" ], "keywords": [ "cluster expansion formulas", "perfect matchings", "laurent polynomial expansion", "study cluster algebras", "principal coefficient systems" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0810.3638M" } } }