{ "id": "1710.06003", "version": "v1", "published": "2017-10-16T21:39:50.000Z", "updated": "2017-10-16T21:39:50.000Z", "title": "On the category of finitely presented mod $p$ representations of $GL_2(F)$, $F/\\mathbb{Q}_p$ finite", "authors": [ "Jack Shotton" ], "comment": "7 pages. Comments and corrections welcomed", "categories": [ "math.RT", "math.NT" ], "abstract": "Let $F$ be a finite extension of $\\mathbb{Q}_p$, and let $\\mathbb{F}$ be a finite field of characteristic $p$. A smooth representation of $GL_2(F)$ over $\\mathbb{F}$ is finitely presented if it can be written as the cokernel of a map between representations induced from compact-mod-centre open subgroups of $GL_2(F)$. We prove that the category of finitely presented smooth representations is an abelian subcategory of all smooth representations. This amounts to showing that the kernel of a map between finitely presented smooth representations is finitely presented. The proof uses amalgamated products of completed group rings.", "revisions": [ { "version": "v1", "updated": "2017-10-16T21:39:50.000Z" } ], "analyses": { "subjects": [ "22E50", "11F70" ], "keywords": [ "smooth representation", "compact-mod-centre open subgroups", "finite field", "finite extension", "abelian subcategory" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable" } } }