Note on almost relative projectives and almost relative injectives
Note on almost relative projectives and almost relative injectives
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关于几乎相对射影和几乎相对射影的注记
DOI:
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发表时间:
1992
期刊:
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通讯作者:
M. Harada
中科院分区:
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作者:
M. Harada
This paper is supplemental to [4], [6] and [7]. We shall show, under assumption of finite length, that when we study almost relative projectives, we may restrict ourselves only to certain special homomorphisms h in the definition of almost relative projectives [6] (see §1). In the similar manner to proof of the above fact, we shall give a criterion for an Λ-module MQ to be almost MIprojective, where R is a perfect ring and Mi is an indecomposable jR-module. We shall obtain, in §3, a generalization of [6], Theorem 1, where direct sums of local modules were studied. In this section we shall show the same property on direct sum of indecomposalbe modules. §§2 and 4 are the dual versions of §§land3.