{ "id": "2106.13866", "version": "v1", "published": "2021-06-25T19:59:05.000Z", "updated": "2021-06-25T19:59:05.000Z", "title": "Certain residual properties of HNN-extensions with central associated subgroups", "authors": [ "E. V. Sokolov" ], "comment": "28 pages, in Russian; an English version will be available soon", "categories": [ "math.GR" ], "abstract": "Suppose that $G$ is a group, $H$ and $K$ are proper isomorphic central subgroups of $G$, and $\\mathfrak{G}$ is an HNN-extension of $G$ with the associated subgroups $H$ and $K$. We prove necessary and sufficient conditions for $\\mathfrak{G}$ to be residually a $\\mathcal{C}$-group, where $\\mathcal{C}$ is a class of groups closed under taking subgroups, extensions, homomorphic images, and Cartesian products of the form $\\prod_{y \\in Y}X_{y}$, where $X, Y \\in \\mathcal{C}$ and $X_{y}$ is an isomorphic copy of $X$ for each $y \\in Y$.", "revisions": [ { "version": "v1", "updated": "2021-06-25T19:59:05.000Z" } ], "analyses": { "subjects": [ "20E26", "20E06" ], "keywords": [ "central associated subgroups", "residual properties", "hnn-extension", "proper isomorphic central subgroups", "cartesian products" ], "note": { "typesetting": "TeX", "pages": 28, "language": "ru", "license": "arXiv", "status": "editable" } } }