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Vestnik Udmurtskogo Universiteta. Matematika. Mekhanika. Komp'yuternye Nauki, 2015, Volume 25, Issue 2, Pages 180–183
(Mi vuu475)
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MATHEMATICS
Example of nonnormal submetrizable space of small cardinality
M. A. Patrakeevab, E. A. Reznichenkoc a Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, ul. S. Kovalevskoi, 16, Yekaterinburg, 620219, Russia
b Institute of Mathematics and Computer Sciences, Ural Federal University, ul. Mira, 19, Yekaterinburg, 620002, Russia
c Department of General Topology and Geometry, Faculty of Mechanics and Mathematics, Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russia
Abstract:
In 1976 K. Alster and T. Przymusiński constructed an example of nonnormal completely regular separable and first-countable topological space of cardinality $\aleph_1$. Also they proved a theorem which implies that under Martin's Axiom with negation of continuum hypothesis there is no similar example, which is additionally cometrizable. If we weaken the cometrizability condition to submetrizability, then the similar statement can not be proved: here we construct an example of nonnormal completely regular submetrizable separable first-countable locally countable space of cardinality $\aleph_1$.
Keywords:
submetrizable space, nonnormal space, cometrizable space.
Received: 19.05.2015
Citation:
M. A. Patrakeev, E. A. Reznichenko, “Example of nonnormal submetrizable space of small cardinality”, Vestn. Udmurtsk. Univ. Mat. Mekh. Komp. Nauki, 25:2 (2015), 180–183
Linking options:
https://www.mathnet.ru/eng/vuu475 https://www.mathnet.ru/eng/vuu/v25/i2/p180
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Abstract page: | 440 | Full-text PDF : | 223 | References: | 64 |
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