首页 | 本学科首页   官方微博 | 高级检索  
     


Groupwise density and related cardinals
Authors:Andreas Blass
Affiliation:(1) Mathematics Department, University of Michigan, 48109 Ann Arbor, MI, USA
Abstract:We prove several theorems about the cardinal
$$mathfrak{g}$$
associated with groupwise density. With respect to a natural ordering of families of nond-ecreasing maps fromohgr toohgr, all families of size
$$< mathfrak{g}$$
are below all unbounded families. With respect to a natural ordering of filters onohgr, all filters generated by
$$< mathfrak{g}$$
sets are below all non-feeble filters. If
$$mathfrak{u}< mathfrak{g}$$
then
$$mathfrak{b}< mathfrak{u}$$
and
$$mathfrak{g} = mathfrak{d} = mathfrak{c}$$
. (The definitions of these cardinals are recalled in the introduction.) Finally, some consequences deduced from
$$mathfrak{u}< mathfrak{g}$$
by Laflamme are shown to be equivalent to
$$mathfrak{u}< mathfrak{g}$$
.
Keywords:
本文献已被 SpringerLink 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