{ "id": "2006.07285", "version": "v1", "published": "2020-06-12T16:09:41.000Z", "updated": "2020-06-12T16:09:41.000Z", "title": "Completions of discrete cluster categories of type $\\mathbb{A}$", "authors": [ "Charles Paquette", "Emine Yildirim" ], "comment": "30 pages, 10 figures", "categories": [ "math.RT" ], "abstract": "We complete the discrete cluster categories of type $\\mathbb{A}$ as defined by Igusa and Todorov, by embedding such a discrete cluster category inside a larger one, and then take a certain Verdier quotient. The resulting category is a Hom-finite Krull-Schmidt triangulated category containing the discrete cluster category as a full subcategory. The objects and Hom-spaces in this new category can be described geometrically, even though the category is not $2$-Calabi-Yau and Ext-spaces are not always symmetric. We describe all cluster-tilting subcategories. Given such a subcategory, we define a cluster character that takes value in a ring with infinitely many indeterminates. Our cluster character is new in that it takes into account infinite dimensional sub-representations of infinite dimensional ones. We show that it satisfies the multiplication formula and also the exchange formula, provided that the objects being exchanged satisfy some local Calabi-Yau conditions.", "revisions": [ { "version": "v1", "updated": "2020-06-12T16:09:41.000Z" } ], "analyses": { "subjects": [ "18E30", "16G20" ], "keywords": [ "completions", "discrete cluster category inside", "account infinite dimensional sub-representations", "cluster character", "subcategory" ], "note": { "typesetting": "TeX", "pages": 30, "language": "en", "license": "arXiv", "status": "editable" } } }