Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-25T06:15:43.376Z Has data issue: false hasContentIssue false

A Regular Space on Which Every Real-Valued Function with a Closed Graph is Constant

Published online by Cambridge University Press:  20 November 2018

Ivan Baggs*
Affiliation:
Department of Mathematics University of Alberta Edmonton, Alberta T6G 2G1 Canada
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

An example is given of a regular space on which every real-valued function with a closed graph is constant. It was previously known that there are regular spaces on which every continuous function is constant. It is also shown here that there are regular spaces that support only constant real-valued continuous functions, but support non-constant real-valued functions with a closed graph.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1989

References

1. Armentrout, A., A Moore space on which every real-valued continuous function is constant, Proc. Amer. Math. Soc. 12 (1961), 106109.Google Scholar
2. Baggs, I., Functions with a closed graph, Proc. Amer. Math. Soc. 43 (1974), 439442.Google Scholar
3. Baggs, I., Nowhere dense sets and real-valued functions with a closed graph, Internat. J. Math, and Math. Sci. 12 (1989), 18.Google Scholar
4. Dobos, J., On the set of points of discontinuity for functions with a closed graph, Cas. Pëst. Mat. 110 (1985), 6068.Google Scholar
5. van, E. K. Douwen, A regular space on which every continuous real-valued function is constant, Niew Archief voor Wiskunde 20 (1972), 143145.Google Scholar
6. Fuller, R. V., Relations amongst continuous and various non-continuous functions, Pac. J. Math. 25 (1968), 495509.Google Scholar
7. Hamlett, T. R. and L. L. Herrington, The closed graph and P-closed graph properties in general topology, Amer. Math. Soc. Contemporary Math. Volume 3, (1980).Google Scholar
8. Herrlich, H., Wann sind aile statigen Abbildungen in Y konstant?, Math. Zeitschr. 90 (1965), 152154.Google Scholar
9. Hewitt, E., On two problems of Urysohn, Annals of Math. 47 (1946), 503509.Google Scholar
10. Iliadis, S. and V. Tzannes, Spaces on which every continuous map into a given space is constant. Can. J. Math. 38 (1986), 12811298.Google Scholar
11. Kostyroko, P., A note on the functions with closed graphs, Cas. Pëst. Mat. 94 (1969), 202205.Google Scholar
12. Long, P. E., Functions with closed graphs, Amer. Math. Monthly 76 (1969), 930932.Google Scholar
13. Novak, J., Regular space on which every continuous function is constant, Časopis Pěst. Mat. Fys. 73 (1948), 5868.Google Scholar
14. Stein, L. A. and Seebach, J. A. Jr., Counterexamples in Topology, Holt, Rinehart and Winston, Inc., 1970.Google Scholar
15. Thomas, J., A regular space, not completely regular, Amer. Math. Monthly, 76 (1969), 181182.Google Scholar
16. Thompson, T., Characterizing certain sets with functions having closed graphs, Boll, del U.M.I., (4) 12 (1979), 327329.Google Scholar
17. Willard, S. W., General Topology, Addison-Wesley, Reading, Mass., 1970.Google Scholar