EXT AND INVERSE LIMITS

摘要

Enochs' proof of the Flat Cover Conjecture is based on a construction of special preenvelopes from [8]. A recent result of Eklof and Shelah implies consistency (with ZFC + GCH) of non-existence of the dual construction of special precovers, for certain abelian groups. By an analysis of Ext on limits of well-ordered inverse systems, we prove that a weaker form of the dual construction is still available (in ZFC), for any module over any ring.