Characters of ultrafilters and tightness of products of fans |
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Authors: | Miroslav Hu&scaron ek |
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Affiliation: | a Charles University, Sokolovská 83, 18675 Prague, Czech Republic b Univerzita J.E.Purkyně, ?eské mláde?e 8, 400 96 Ústí nad Labem, Czech Republic |
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Abstract: | As applications of productivity of coreflective classes of topological spaces, the following results will be proved: (1) Characters of points of βN?N are not smaller than any submeasurable cardinal less or equal to ω2. (2) If κ is a submeasurable cardinal and S is a sequential fan with κ many spines then the tightness of the κ-power of S is equal to κ. In fact, a little more general results are proved. |
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Keywords: | 54A25 03E10 |
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