Properties of RD-projective and RD-injective modules

In this paper, we first study RD-projective and RD-injective modules using, among other things, covers and envelopes. Some new characterizations for them are obtained. Then we introduce the RD-projective and RD-injective dimensions for modules and rings. The relations between the RD-homological dimensions and other homological dimensions are also investigated.

Anahtar Kelimeler:

RD-projective module, RD-injective module, RD-flat module, RD-projective dimension, RD-injective dimension, (pre)envelope, (pre)cover

Properties of RD-projective and RD-injective modules

Keywords:

RD-projective module, RD-injective module, RD-flat module, RD-projective dimension, RD-injective dimension, (pre)envelope, (pre)cover,

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Institute of Mathematics, Nanjing Institute of Technology, Nanjing 211167, CHINA e-mail: maolx2@hotmail.com