{ "id": "1608.01784", "version": "v1", "published": "2016-08-05T07:17:53.000Z", "updated": "2016-08-05T07:17:53.000Z", "title": "The Breuil--Mézard conjecture when $l \\neq p$", "authors": [ "Jack Shotton" ], "comment": "51 pages. Submitted", "categories": [ "math.NT" ], "abstract": "Let $l$ and $p$ be primes, let $F/\\mathbb{Q}_p$ be a finite extension with absolute Galois group $G_F$, let $\\mathbb{F}$ be a finite field of characteristic $l$, and let $\\bar{\\rho} : G_F \\rightarrow GL_n(\\mathbb{F})$ be a continuous representation. Let $R^\\square(\\bar{\\rho})$ be the universal framed deformation ring for $\\bar{\\rho}$. If $l = p$, then the Breuil--M\\'{e}zard conjecture (as formulated by Emerton and Gee) relates the mod $l$ reduction of certain cycles in $R^\\square(\\bar{\\rho})$ to the mod $l$ reduction of certain representations of $GL_n(\\mathcal{O}_F)$. We state an analogue of the Breuil--M\\'{e}zard conjecture when $l \\neq p$, and prove it whenever $l > 2$ using automorphy lifting theorems. We give a local proof when $l$ is \"quasi-banal\" for $F$ and $\\bar{\\rho}$ is tamely ramified. We also analyse the reduction modulo $l$ of the types $\\sigma(\\tau)$ defined by Schneider and Zink.", "revisions": [ { "version": "v1", "updated": "2016-08-05T07:17:53.000Z" } ], "analyses": { "keywords": [ "breuil-mézard conjecture", "absolute galois group", "reduction modulo", "finite field", "finite extension" ], "note": { "typesetting": "TeX", "pages": 51, "language": "en", "license": "arXiv", "status": "editable" } } }