{ "id": "1811.09741", "version": "v1", "published": "2018-11-24T01:49:36.000Z", "updated": "2018-11-24T01:49:36.000Z", "title": "Curves with prescribed symmetry and associated representations of mapping class groups", "authors": [ "Marco Boggi", "Eduard Looijenga" ], "categories": [ "math.AG", "math.AT" ], "abstract": "Let C be a complex smooth projective algebraic curve endowed with an action of a finite group G such that the quotient curve has genus at least 3. We prove that if the G-curve C is very general for these properties, then the natural map from the group algebra QG to the algebra of Q-endomorphisms of its Jacobian is an isomorphism. We use this to obtain (topological) properties regarding certain virtual linear representations of a mapping class group. For example, we show that the connected component of the Zariski closure of such a representation acts Q-irreducibly in a G-isogeny space of H^1(C; Q)and with image often a Q-almost simple group.", "revisions": [ { "version": "v1", "updated": "2018-11-24T01:49:36.000Z" } ], "analyses": { "subjects": [ "14H40", "14H37", "32G15" ], "keywords": [ "mapping class group", "associated representations", "prescribed symmetry", "complex smooth projective algebraic curve", "virtual linear representations" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }