{ "id": "2207.00920", "version": "v1", "published": "2022-07-02T23:45:49.000Z", "updated": "2022-07-02T23:45:49.000Z", "title": "Stable rational homology of the IA-automorphism groups of free groups", "authors": [ "Mai Katada" ], "comment": "55 pages", "categories": [ "math.AT" ], "abstract": "The rational homology of the IA-automorphism group $\\operatorname{IA}_n$ of the free group $F_n$ is still mysterious. We study the quotient of the rational homology of $\\operatorname{IA}_n$ that is obtained as the image of the map induced by the abelianization map, which we call the Albanese homology of $\\operatorname{IA}_n$. We obtain a representation-stable $\\operatorname{GL}(n,\\mathbb{Q})$-subquotient of the Albanese homology of $\\operatorname{IA}_n$, which conjecturally coincides with the entire Albanese homology of $\\operatorname{IA}_n$. In particular, we obtain a lower bound of the dimension of the Albanese homology of $\\operatorname{IA}_n$ for each homological degree in a stable range. Moreover, we determine the entire third Albanese homology of $\\operatorname{IA}_n$ for $n\\ge 9$. We also study the Albanese homology of an analogue of $\\operatorname{IA}_n$ to the outer automorphism group of $F_n$.", "revisions": [ { "version": "v1", "updated": "2022-07-02T23:45:49.000Z" } ], "analyses": { "subjects": [ "20F28", "20J06" ], "keywords": [ "stable rational homology", "ia-automorphism group", "free group", "entire third albanese homology", "outer automorphism group" ], "note": { "typesetting": "TeX", "pages": 55, "language": "en", "license": "arXiv", "status": "editable" } } }