{ "id": "2207.13072", "version": "v1", "published": "2022-07-26T17:42:53.000Z", "updated": "2022-07-26T17:42:53.000Z", "title": "Embeddings of automorphism groups of free groups into automorphism groups of affine algebraic varieties", "authors": [ "Vladimir L. Popov" ], "comment": "14 pages", "categories": [ "math.AG" ], "abstract": "A new infinite series of rational affine algebraic varieties is constructed whose automorphism group contains the automorphism group ${\\rm Aut}(F_n)$ of the free group $F_n$ of rank $n$. The automorphism groups of such varieties are nonlinear and contain the braid group $B_n$ on $n$ strands for $n\\geqslant 3$, and are nonamenable for $n\\geqslant 2$. As an application, it is proved that for $n\\geqslant 3$, every Cremona group of rank $\\geqslant 3n-1$ contains the groups ${\\rm Aut}(F_n)$ and $B_n$. This bound is 1 better than the one published earlier by the author; with respect to $B_n$ the order of its growth rate is one less than that of the bound following from the paper by D. Krammer. The basis of the construction are triplets $(G, R, n)$, where $G$ is a connected semisimple algebraic group and $R$ is a closed subgroup of its maximal torus.", "revisions": [ { "version": "v1", "updated": "2022-07-26T17:42:53.000Z" } ], "analyses": { "subjects": [ "14L30", "14M99", "20F28", "20F29", "20F38" ], "keywords": [ "free group", "embeddings", "rational affine algebraic varieties", "automorphism group contains", "connected semisimple algebraic group" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }