Applications of a set-theoretic lemma
HTML articles powered by AMS MathViewer
- by Gary Gruenhage PDF
- Proc. Amer. Math. Soc. 92 (1984), 133-140 Request permission
Abstract:
A set-theoretic lemma is introduced and various applications are given, including: (1) a result of Erdös and Hajnal on the coloring number of a graph; (2) game characterizations of the coloring number of a graph; (3) K. Alster’s result that a point-countable collection of open, compact scattered spaces has a point-finite clopen refinement; (4) normal, locally compact, metacompact spaces which are scattered of finite height are paracompact.References
- K. Alster, Some remarks on Eberlein compacts, Fund. Math. 104 (1979), no. 1, 43–46. MR 549380, DOI 10.4064/fm-104-1-43-46
- A. V. Arhangel′skiĭ, The property of paracompactness in the class of perfectly normal locally bicompact spaces, Dokl. Akad. Nauk SSSR 203 (1972), 1231–1234 (Russian). MR 0305342
- Dennis K. Burke, Closed mappings, Surveys in general topology, Academic Press, New York-London-Toronto, Ont., 1980, pp. 1–32. MR 564098 —, Characterizations of meta-Lindelöf and related spaces (preprint).
- Peg Daniels, Normal, locally compact, boundedly metacompact spaces are paracompact: an application of Pixley-Roy spaces, Canad. J. Math. 35 (1983), no. 5, 807–823. MR 735898, DOI 10.4153/CJM-1983-046-x
- P. Erdős and A. Hajnal, On chromatic number of graphs and set-systems, Acta Math. Acad. Sci. Hungar. 17 (1966), 61–99. MR 193025, DOI 10.1007/BF02020444
- Gary Gruenhage, Paracompactness in normal, locally connected, locally compact spaces, Topology Proc. 4 (1979), no. 2, 393–405 (1980). MR 598283 —, Covering properties on ${X^2}\backslash \Delta$, $W$-sets, and compact subsets of $\Sigma$-products, Topology Appl. (to appear).
- G. Gruenhage and E. Michael, A result on shrinkable open covers, Proceedings of the 1983 topology conference (Houston, Tex., 1983), 1983, pp. 37–43. MR 738467
- G. Gruenhage, E. Michael, and Y. Tanaka, Spaces determined by point-countable covers, Pacific J. Math. 113 (1984), no. 2, 303–332. MR 749538
- Franklin D. Tall, On the existence of normal metacompact Moore spaces which are not metrizable, Canadian J. Math. 26 (1974), 1–6. MR 377823, DOI 10.4153/CJM-1974-001-8 —, The countable chain condition versus separability-applications of Martin’s Axiom, General Topology Appl. 2 (1974), 315-339.
- W. Stephen Watson, Locally compact normal spaces in the constructible universe, Canadian J. Math. 34 (1982), no. 5, 1091–1096. MR 675681, DOI 10.4153/CJM-1982-078-8
Additional Information
- © Copyright 1984 American Mathematical Society
- Journal: Proc. Amer. Math. Soc. 92 (1984), 133-140
- MSC: Primary 54D18; Secondary 04A20, 05C15
- DOI: https://doi.org/10.1090/S0002-9939-1984-0749905-3
- MathSciNet review: 749905