On the cardinality of n-Urysohn and n-Hausdorff spaces.

Autor: Bonanzinga, Maddalena, Cuzzupé, Maria V., Pansera, Bruno A.
Zdroj: Central European Journal of Mathematics; Feb2014, Vol. 12 Issue 2, p330-336, 7p
Abstrakt: Two variations of Arhangelskii’s inequality $$\left| X \right| \leqslant 2^{\chi (X) - L(X)}$$ for Hausdorff X [Arhangel’skii A.V., The power of bicompacta with first axiom of countability, Dokl. Akad. Nauk SSSR, 1969, 187, 967–970 (in Russian)] given in [Stavrova D.N., Separation pseudocharacter and the cardinality of topological spaces, Topology Proc., 2000, 25(Summer), 333–343] are extended to the classes with finite Urysohn number or finite Hausdorff number. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index