Weakly automorphism invariant modules and essential tightness

Kosan M. T., Truong Cong Quynh T. C. Q., Sahinkaya S.

COMMUNICATIONS IN ALGEBRA, cilt.45, sa.8, ss.3531-3541, 2017 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 45 Sayı: 8
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1080/00927872.2016.1238094
  • Dergi Adı: COMMUNICATIONS IN ALGEBRA
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.3531-3541
  • Gazi Üniversitesi Adresli: Hayır

Özet

While a module is pseudo-injective if and only if it is automorphism-invariant, it was not known whether automorphism-invariant modules are tight. It is shown that weakly automorphism-invariant modules are precisely essentially tight. We give various examples of weakly automorphism-invariant and essentially tight modules and study their properties. Some particular results: (1) R is a semiprime right and left Goldie ring if and only if every right (left) ideal is weakly injective if and only if every right (left) ideal is weakly automorphism invariant; (2) R is a CEP-ring if and only if R is right artinian and every indecomposable projective right R-module is uniform and essentially R-tight.