{ "id": "0708.2819", "version": "v1", "published": "2007-08-21T11:59:53.000Z", "updated": "2007-08-21T11:59:53.000Z", "title": "On the cyclic subgroup separability of free products of two groups with amalgamated subgroup", "authors": [ "E. V. Sokolov" ], "comment": "10 pages; for other papers of this author, see http://icu.ivanovo.ac.ru/tg-seminar", "journal": "Lobachevskii Journal of Mathematics. 11 (2002). 27-38", "categories": [ "math.GR" ], "abstract": "Let $G$ be a free product of two groups with amalgamated subgroup, $\\pi$ be either the set of all prime numbers or the one-element set \\{$p$\\} for some prime number $p$. Denote by $\\Sigma$ the family of all cyclic subgroups of group $G$, which are separable in the class of all finite $\\pi$-groups. Obviously, cyclic subgroups of the free factors, which aren't separable in these factors by the family of all normal subgroups of finite $\\pi$-index of group $G$, the subgroups conjugated with them and all subgroups, which aren't $\\pi^{\\prime}$-isolated, don't belong to $\\Sigma$. Some sufficient conditions are obtained for $\\Sigma$ to coincide with the family of all other $\\pi^{\\prime}$-isolated cyclic subgroups of group $G$. It is proved, in particular, that the residual $p$-finiteness of a free product with cyclic amalgamation implies the $p$-separability of all $p^{\\prime}$-isolated cyclic subgroups if the free factors are free or finitely generated residually $p$-finite nilpotent groups.", "revisions": [ { "version": "v1", "updated": "2007-08-21T11:59:53.000Z" } ], "analyses": { "subjects": [ "20E06", "20E26" ], "keywords": [ "free product", "cyclic subgroup separability", "amalgamated subgroup", "isolated cyclic subgroups", "prime number" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0708.2819S" } } }