{ "id": "1909.03357", "version": "v1", "published": "2019-09-08T00:48:51.000Z", "updated": "2019-09-08T00:48:51.000Z", "title": "A van Douwen-like ZFC theorem for small powers of countably compact groups without non-trivial convergent sequences", "authors": [ "Artur Hideyuki Tomita" ], "journal": "Topology Appl. Volume 259, 1 June 2019, Pages 347-364", "doi": "10.1016/j.topol.2019.02.040", "categories": [ "math.GN" ], "abstract": "We show that if $\\kappa \\leq \\omega$ and there exists a group topology without non-trivial convergent sequences on an Abelian group $H$ such that $H^n$ is countably compact for each $n<\\kappa$ then there exists a topological group $G$ such that $G^n$ is countably compact for each $n <\\kappa$ and $G^{\\kappa}$ is not countably compact. If in addition $H$ is torsion, then the result above holds for $\\kappa=\\omega_1$. Combining with other results in the literature, we show that: $a)$ Assuming ${\\mathfrak c}$ incomparable selective ultrafilters, for each $n \\in \\omega$, there exists a group topology on the free Abelian group $G$ such that $G^n$ is countably compact and $G^{n+1}$ is not countably compact. (It was already know for $\\omega$). $b)$ If $\\kappa \\in \\omega \\cup \\{\\omega\\} \\cup \\{\\omega_1\\}$, there exists in ZFC a topological group $G$ such that $G^\\gamma$ is countably compact for each cardinal $\\gamma <\\kappa$ and $G^\\kappa$ is not countably compact.", "revisions": [ { "version": "v1", "updated": "2019-09-08T00:48:51.000Z" } ], "analyses": { "keywords": [ "van douwen-like zfc theorem", "non-trivial convergent sequences", "countably compact groups", "small powers", "abelian group" ], "tags": [ "journal article" ], "publication": { "publisher": "Elsevier" }, "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }