Modules $M$ such that $\Ext_R^1(M,-)$ commutes with direct limits

Abstract

We will use Watts's theorem together with Lenzing's characterization of finitely presented modules via commuting properties of the induced tensor functor in order to study commuting properties of Ext-covariant functors.

arXiv commentVersion 3. Minor changes; to appear in Algebras and Representation Theory. Version 2: Major changes: more explanation and connected results are added at several places. Reference list was updated and extended