Projectivity and flatness over the endomorphism ring of a finitely generated module

Let A be a ring and Λ a finitely generated A-module. We give necessary and sufficient conditions for projectivity and flatness of a module over the endomorphism ring of Λ

© Hindawi Publishing Corp. PROJECTIVITY AND FLATNESS OVER THE ENDOMORPHISM RING OF A FINITELY GENERATED MODULE

Let A be a ring and Λ a finitely generated A-module. We give necessary and sufficient conditions for projectivity and flatness of a module over the endomorphism ring of Λ. 2000 Mathematics Subject Classification: 16D40, 16W30. 1. Introduction. Suppos