Non-perfect rings and a theorem of Eklof and Shelah. (English) Zbl 0742.16001

Trlifaj, Jan

Commentat. Math. Univ. Carol. 32, No. 1, 27-32 (1991).

The author proves a stronger form of a consistency result due to Eklof and Shelah, concerning extension properties of modules over non-left perfect rings and related to the Whitehead property. He also shows that the result of Eklof and Shelah is the best possible in the sense that, in ZFC, it does not hold for left perfect rings.

Reviewer: J.L.Gómez Pardo (Murcia)

MSC:

16D40	Free, projective, and flat modules and ideals in associative algebras
16L30	Noncommutative local and semilocal rings, perfect rings
03E55	Large cardinals

Keywords:

\(\kappa^ +\)-free module; projective module; consistency; extension properties; Whitehead property; ZFC; left perfect rings