论文信息 - Exact envelopes of complexes

Exact envelopes of complexes

It is known that every complex of left R-modules has an exact cover. We consider the question of finding R for which every complex of left i?-modules has an exact envelope. We first give a simple proof that for every R every complex of left R-modules has a special exact preenvelope and then use this to show that the left perfect rings are those R for which every complex has an exact envelope. So, for example, this result holds for all artinian rings.

G. J. Rozas | E. Enochs

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