Rad-Projective 𝛿-Covers
Yasser Ibrahim, Mohamed F. Yousif · Contemporary mathematics - American Mathematical Society · 2015
In generalizing the well-established notion of projective cover, the notions of D 3 D3 -cover and r a d rad -projective cover were recently introduced and new characterizations of perfect and semiperfect rings were provided. On the other hand, Y. Zhou introduced and studied the notions of δ \delta -cover, δ \delta -perfect and δ \delta -semiperfect rings. In this paper we combine and generalize these notions and introduce the new notions of r a d rad -projective δ \delta -cover and D 3 D3 - δ \delta -cover. New characterizations of δ \delta -perfect and δ \delta -semiperfect rings are provided.