Character modules, submodules of a free module, and quasi-Frobenius rings.
Characterizations of semiperfect and perfect rings.
We characterize semiperfect modules, semiperfect rings, and perfect rings using locally projective covers and generalized locally projective covers, where locally projective modules were introduced by Zimmermann-Huisgen and generalized locally projective covers are adapted from Azumaya’s generalized projective covers.
Coefficient subrings of certain local rings with prime-power characteristic.
Cofinitely semiperfect modules.