{ "id": "1110.0082", "version": "v2", "published": "2011-10-01T07:25:19.000Z", "updated": "2012-03-04T05:36:52.000Z", "title": "On rectifiable spaces and paratopological groups", "authors": [ "Fucai Lin", "Rongxin Shen" ], "comment": "19 pages (replace)", "journal": "Topology and its Applications, 158(2011), 597-610", "doi": "10.1016/j.topol.2010.12.008", "categories": [ "math.GN", "math.GR" ], "abstract": "We mainly discuss the cardinal invariants and generalized metric properties on paratopological groups or rectifiable spaces, and show that: (1) If $A$ and $B$ are $\\omega$-narrow subsets of a paratopological group $G$, then $AB$ is $\\omega$-narrow in $G$, which give an affirmative answer for \\cite[Open problem 5.1.9]{A2008}; (2) Every bisequential or weakly first-countable rectifiable space is metrizable; (3) The properties of Fr$\\acute{e}$chet-Urysohn and strongly Fr$\\acute{e}$chet-Urysohn are coincide in rectifiable spaces; (4) Every rectifiable space $G$ contains a (closed) copy of $S_{\\omega}$ if and only if $G$ has a (closed) copy of $S_{2}$; (5) If a rectifiable space $G$ has a $\\sigma$-point-discrete closed $k$-network, then $G$ contains no closed copy of $S_{\\omega_{1}}$; (6) If a rectifiable space $G$ is pointwise canonically weakly pseudocompact, then $G$ is a Moscow space. Also, we consider the remainders of paratopological groups or rectifiable spaces, and give a partial answer to questions posed by C. Liu in \\cite{Liu2009} and C. Liu, S. Lin in \\cite{Liu20091}, respectively.", "revisions": [ { "version": "v2", "updated": "2012-03-04T05:36:52.000Z" } ], "analyses": { "subjects": [ "54A25", "54B05", "54E20", "54E35" ], "keywords": [ "paratopological group", "narrow subsets", "cardinal invariants", "chet-urysohn", "generalized metric properties" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1110.0082L" } } }