{ "id": "2001.04956", "version": "v1", "published": "2020-01-14T18:28:31.000Z", "updated": "2020-01-14T18:28:31.000Z", "title": "Galois deformation spaces with a sparsity of automorphic points", "authors": [ "Kevin Childers" ], "comment": "39 pages", "categories": [ "math.NT" ], "abstract": "Let $k/\\mathbb F_p$ denote a finite field. For any split connected reductive group $G/W(k)$ and certain CM number fields $F$, we deform certain Galois representations $\\overline\\rho:Gal(\\overline F/F) \\to G(k)$ to continuous families $X_{\\overline\\rho}$ of Galois representations $Gal(\\overline F/F) \\to G(\\overline{\\mathbb Q_p})$ lifting $\\overline\\rho$ such that the space of points of $X_{\\overline\\rho}$ which are geometric (in the sense of the Fontaine-Mazur conjecture) with parallel Hodge-Tate weights has positive codimension in $X_{\\overline\\rho}$. Thus the set of points in $X_{\\overline\\rho}$ which could (conjecturally) be associated to automorphic forms is sparse. This generalizes a result of Calegari and Mazur for $F/\\mathbb Q$ quadratic imaginary and $G = GL_2$. The sparsity of automorphic points for $F$ a CM field contrasts with the situation when $F$ is a totally real field, where automorphic points are often provably dense.", "revisions": [ { "version": "v1", "updated": "2020-01-14T18:28:31.000Z" } ], "analyses": { "keywords": [ "galois deformation spaces", "automorphic points", "galois representations", "cm field contrasts", "cm number fields" ], "note": { "typesetting": "TeX", "pages": 39, "language": "en", "license": "arXiv", "status": "editable" } } }