Journal of Lanzhou University of Technology ›› 2020, Vol. 46 ›› Issue (4): 154-156.

• Scientific • Previous Articles     Next Articles

D4-δ-covers and their applications

WANG Yong-duo, WANG Ya-ting   

  1. School of Science, Lanzhou Univ. of Tech., Lanzhou 730050, China
  • Received:2018-07-12 Online:2020-08-28 Published:2020-11-10

Abstract: The concept of D4-δ-covers is introduced. A pair (F,g) is called a D4-δ-cover of a module M if F is a D4-δ-module, g an epimorphism of F onto M, and Ker(g)《δF. The properties of D4-δ-cover and their relations to projective δ-cover are studied and δ-perfect rings (semiperfect rings, semiregular rings) are characterized by using D4-δ-covers.

Key words: D4-δ-cover, δ-perfect ring, δ-semiperfect ring, δ-semiregular ring

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