{ "id": "1804.06840", "version": "v1", "published": "2018-04-18T17:59:11.000Z", "updated": "2018-04-18T17:59:11.000Z", "title": "The Mumford--Tate conjecture for products of abelian varieties", "authors": [ "Johan Commelin" ], "comment": "34 pages. All comments are welcome!", "categories": [ "math.AG" ], "abstract": "Let $X$ be a smooth projective variety over a finitely generated field $K$ of characteristic~$0$ and fix an embedding $K \\subset \\mathbb{C}$. The Mumford--Tate conjecture is a precise way of saying that certain extra structure on the $\\ell$-adic \\'etale cohomology groups of~$X$ (namely, a Galois representation) and certain extra structure on the singular cohomology groups of~$X$ (namely, a Hodge structure) convey the same information. The main result of this paper says that if $A_1$ and~$A_2$ are abelian varieties (or abelian motives) over~$K$, and the Mumford--Tate conjecture holds for both~$A_1$ and~$A_2$, then it holds for $A_1 \\times A_2$. These results do not depend on the embedding $K \\subset \\CC$.", "revisions": [ { "version": "v1", "updated": "2018-04-18T17:59:11.000Z" } ], "analyses": { "keywords": [ "abelian varieties", "extra structure", "adic etale cohomology groups", "mumford-tate conjecture holds", "singular cohomology groups" ], "note": { "typesetting": "TeX", "pages": 34, "language": "en", "license": "arXiv", "status": "editable" } } }