Envelopes and Covers by Modules of Finit
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S.Tempest Aldrich; Edgar E. Enochs; Overtoun M.G. Jenda; Luis Oyonarte
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Article
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2001
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Elsevier Science
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English
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In this paper, we study the existence of โฅ -envelopes, -envelopes, โฅ -envelopes, -covers, and -covers where and denote the classes of modules of injective and projective dimension less than or equal to a natural number n, respectively. We prove that over any ring R, special โฅ -preenvelopes and speci