On kernels of cellular covers

被引:17
|
作者
Farjoun, Emmanuel D. [1 ]
Gobel, Rudiger [2 ]
Segev, Yoav [3 ]
Shelah, Saharon
机构
[1] Hebrew Univ Jerusalem, Inst Math, IL-91904 Jerusalem, Israel
[2] Univ Duisburg Essen, Fachbereich Math, D-45117 Essen, Germany
[3] Ben Gurion Univ Negev, Dept Math, IL-84105 Beer Sheva, Israel
关键词
cellular cover; infinite cardinal; free abelian group;
D O I
10.4171/GGD/20
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
In the present paper we continue to examine cellular covers of groups, focusing on the cardinality and the structure of the kernel K of the cellular map G -> M. We show that in general a torsion free reduced abelian group M may have a proper class of non- isomorphic cellular covers. In other words, the cardinality of the kernels is unbounded. In the opposite direction we show that if the kernel of a cellular cover of any group M has certain "freeness" properties, then its cardinality is bounded by vertical bar M vertical bar.
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页码:409 / 419
页数:11
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