Weak diamond, weak projectivity, and transfinite extensions of simple artinian rings

Abstract

We apply set-theoretic methods to study projective modules and their generalizations over transfinite extensions of simple artinian rings R. When R is hereditary and of cardinality at most $2^{\omega }$, we prove that the Weak Diamond and CH imply that projectivity of an arbitrary module can be tested at the layer epimorphisms of R.

The updated version of this paper appears as arXiv:2203.06005 above