Applications of automatic quasi-continuity
Abstract
We study quasi-continuous functions on the product of two spaces provided they are separately continuous. We apply our results to actions of (semi-) groups on topological spaces and to the problem of the uniqueness of extensions of separately continuous functions.
Keywords
semi-continuity; Baire number; separate continuity
References
2. Baire R., Sur les functions de variables reelles, Ann. Mat. Pura Appl., 3 (1898), 1-123.
3. Breckenridge J., Nishiura T., Partial continuity, quasicontinuity, and Baire spaces, Bull. of the Inst. of Mathematics Acad. Sinica, 4 (1976), 191-203.
4. Comfort W., Functions linearaly continuous on a product of Baire spaces, Boll. Un. Mat. Ital., 20 (1965), 128-134.
5. Debs G., Une classe de compacts satisfaint le theoreme de Namioka sur les functions separement continues, preprint.
6. Engelking R., General Topology, Polish Sci. Publisher, Warszawa 1977.
7. Fleissner W., Kunen K., Barely Baire spaces, Fundamenta Mathematicae, 101 (1978), 228-240.
8. Goffman C., Neugebauer C., Linearly continuous functions, Proceedings of the American Mathematical Society, 12 (1961), 997-998.
9. Juhász I., Cardinal Functions — Ten Years Later, Math. Centre Tract, 123 (1980), Amsterdam.
10. Kempisty S., Sur les fonctions quasicontinues, Fund. Math., 19 (1932), 184-197.
11. Kuratowski K., Topology, vol. I, Academic Press, PWN, Warszawa 1966.
12. Micheal E., Namioka I., Barely continuous functions, Bull. de l'Acad. Polon. des Sci, Serie des sci. Math., Astr. et Phys., 24 (1976), 889-892.
13. Namioka I., Separate continuity and joint continuity, Pacific Journ. of Mathematics, 51 (1974), 515-531.
14. Neubrunn T., Quasi-continuity, Real Anal. Exchange, 14 (1988-1989), 259-306.
15. Piotrowski Z., Separate and joint continuity, Real Anal. Exchange, 11 (1985-1986), 293-321.
16. Saint Raymond J., Jeux topologique et espaces de Namioka, Proceedings of the American Mathematical Society, 87 (1983), 499-504.
17. Sierpiński W., Sur une priopriete de fonctions de deux variables reelles continues par rapport a chacune de variables, Publ. Math. Univ. Belgrade, 1 (1932), 125-128.
Instytut Matematyki, Uniwersytet Śląski w Katowicach Poland
Department of Mathematics, Slippery Rock University, USA United States
The Copyright Holders of the submitted text are the Author and the Journal. The Reader is granted the right to use the pdf documents under the provisions of the Creative Commons 4.0 International License: Attribution (CC BY). The user can copy and redistribute the material in any medium or format and remix, transform, and build upon the material for any purpose.
- License
This journal provides immediate open access to its content under the Creative Commons BY 4.0 license (http://creativecommons.org/licenses/by/4.0/). Authors who publish with this journal retain all copyrights and agree to the terms of the above-mentioned CC BY 4.0 license. - Author’s Warranties
The author warrants that the article is original, written by stated author/s, has not been published before, contains no unlawful statements, does not infringe the rights of others, is subject to copyright that is vested exclusively in the author and free of any third party rights, and that any necessary written permissions to quote from other sources have been obtained by the author/s. - User Rights
Under the Creative Commons Attribution license, the users are free to share (copy, distribute and transmit the contribution) and adapt (remix, transform, and build upon the material) the article for any purpose, provided they attribute the contribution in the manner specified by the author or licensor. - Co-Authorship
If the article was prepared jointly with other authors, the signatory of this form warrants that he/she has been authorized by all co-authors to sign this agreement on their behalf, and agrees to inform his/her co-authors of the terms of this agreement.