Universal groups, binate groups and acyclicity
Universal groups, binate groups and acyclicity
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全群、二元群和无环性
DOI:
10.1515/9783110848397-019
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发表时间:
1989
期刊:
影响因子:
--
通讯作者:
Y. K. Leong
中科院分区:
文献类型:
--
作者:
A. Berrick;K. N. Cheng;Y. K. Leong
In [3 p85] it is stated that Lemma 11.11, used to prove the acyclicity (triviality of homology with trivial integer coefficients) of a certain universal group in algebraic iT-theory, "serves to establish the acyclicity of many other groups besides, but that, as they say, is another story". This work presents that other story. The key property of groups under consideration is a binate ("arranged in pairs") structure conforming to the hypotheses of [3 (11.11)]. We begin with a theoretical consideration of such structures and then offer a list of examples. Almost all the examples were previously known to be acyclic groups; however the arguments given in the literature tend to be of an ad hoc nature, with analogies on occasion noted though not explored. A number of these groups are universal in some sense. One newcomer to the list (in that it has not previously been described as acyclic) is P. Hall's countable universal locally finite group. There is another way in which universality enters into this discussion. We begin by considering groups which are universal among binate groups.