首页 | 本学科首页   官方微博 | 高级检索  
     


Characters of ultrafilters and tightness of products of fans
Authors:Miroslav Hu&scaron  ek
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
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.
Keywords:54A25   03E10
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号