Relative Projective Modules and Relative Injective Modules |
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| Authors: | Lixin Mao |
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| Affiliation: | 1. Department of Basic Courses , Nanjing Institute of Technology , Nanjing, China;2. Department of Mathematics , Nanjing University , Nanjing, China |
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| Abstract: | Let R be a ring, and n and d fixed non-negative integers. An R-module M is called (n, d)-injective if Ext d+1 R (P, M) = 0 for any n-presented R-module P. M is said to be (n, d)-projective if Ext1 R (M, N) = 0 for any (n, d)-injective R-module N. We use these concepts to characterize n-coherent rings and (n, d)-rings. Some known results are extended. |
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| Keywords: | Cotorsion theory n-coherent ring (n, d)-injective module (n, d)-projective module (n, d)-ring |
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