{ "id": "2305.16054", "version": "v1", "published": "2023-05-25T13:37:28.000Z", "updated": "2023-05-25T13:37:28.000Z", "title": "Profinite genus of free products with finite amalgamation", "authors": [ "Vagner R. de Bessa", "Anderson L. P. Porto", "Pavel A. Zalesskii" ], "categories": [ "math.GR" ], "abstract": "A finitely generated residually finite group $G$ is an $\\widehat{OE}$-group if any action of its profinite completion $\\widehat G$ on a profinite tree with finite edge stabilizers admits a global fixed point. In this paper, we study the profinite genus of free products $G_1*_HG_2$ of $\\widehat{OE}$-groups $G_1,G_2$ with finite amalgamation $H$. Given such $G_1,G_2,H$ we give precise formulas for the number of isomorphism classes of $G_1*_HG_2$ and of its profinite completion. We compute the genus of $G_1*_HG_2$ and list various situations when the formula for the genus simplifies.", "revisions": [ { "version": "v1", "updated": "2023-05-25T13:37:28.000Z" } ], "analyses": { "keywords": [ "profinite genus", "free products", "finite amalgamation", "generated residually finite group", "finite edge stabilizers admits" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }