{ "id": "2404.06623", "version": "v1", "published": "2024-04-09T21:16:19.000Z", "updated": "2024-04-09T21:16:19.000Z", "title": "Quasiorders for a characterization of iso-dense spaces", "authors": [ "Tom Richmond", "Eliza Wajch" ], "categories": [ "math.GN", "math.LO" ], "abstract": "A (generalized) topological space is called an iso-dense space if the set of all its isolated points is dense in the space. The main aim of the article is to show in $\\mathbf{ZF}$ a new characterization of iso-dense spaces in terms of special quasiorders. For a non-empty family $\\mathcal{A}$ of subsets of a set $X$, a quasiorder $\\lesssim_{\\mathcal{A}}$ on $X$ determined by $\\mathcal{A}$ is defined. Necessary and sufficient conditions for $\\mathcal{A}$ are given to have the property that the topology consisting of all $\\lesssim_{\\mathcal{A}}$-increasing sets coincides with the generalized topology on $X$ consisting of the empty set and all supersets of non-empty members of $\\mathcal{A}$. The results obtained, applied to the quasiorder $\\lesssim_{\\mathcal{D}}$ determined by the family $\\mathcal{D}$ of all dense sets of a given (generalized) topological space, lead to a new characterization of non-trivial iso-dense spaces. Independence results concerning resolvable spaces are also obtained.", "revisions": [ { "version": "v1", "updated": "2024-04-09T21:16:19.000Z" } ], "analyses": { "subjects": [ "54A05", "54A10", "54F05", "54F30", "54G12", "06A75", "06F30", "54A35", "03E35" ], "keywords": [ "characterization", "independence results concerning resolvable spaces", "non-trivial iso-dense spaces", "topological space", "special quasiorders" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }