Group homomorphisms inducing isomorphisms in cohomology |
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Authors: | Dave Benson Leonard Evens |
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Institution: | 1. Mathematical Institute , 24-29 St. Giles, Oxford, OX1 3LB;2. Department of Mathematics , Northwestern University , Evanston, IL, 60208 |
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Abstract: | In this article, we call a ring R right generalized semiregular if for any a ∈ R there exist two left ideals P, L of R such that lr(a) = P⊕ L, where P ? Ra and Ra ∩ L is small in R. The class of generalized semiregular rings contains all semiregular rings and all AP-injective rings. Some properties of these rings are studied and some results about semiregular rings and AP-injective rings are extended. In addition, we call a ring R semi-π-regular if for any a ∈ R there exist a positive integer n and e 2 = e ∈ a n R such that (1 ? e)a n ∈ J(R), the Jacobson radical of R. It is shown that a ring R is semi-π-regular if and only if R/J(R) is π-regular and idempotents can be lifted modulo J(R). |
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Keywords: | Exchange rings AP-injective rings Semi-π-regular rings Generalized semiregular rings |
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