The torsion theory generated by M-small modules

Ozcan A. Ç. , HARMANCI A.

ALGEBRA COLLOQUIUM, cilt.10, sa.1, ss.41-52, 2003 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 10 Konu: 1
  • Basım Tarihi: 2003
  • Doi Numarası: 10.1007/s100110300006
  • Sayfa Sayıları: ss.41-52


Let M be a right R-module, M the class of all M-small modules, and P a projective cover of M in sigma[M]. We consider the torsion theories tau(M) = (TM,.FM), tauv = (Tv, Fv), and taup = (Tp, Fp) in sigma[M], where tau(M) is the torsion theory generated by M, tauv is the torsion theory cogenerated by M, and taup is the dual Lambek torsion theory. We study some conditions for tau(M) to be cohereditary, stable, or split, and prove that Rej (M, M) = M double left right arrow Fp = M (= TM = Fv) double left right arrow Tp = Tv Gen(M) (P) subset of or equal to Tv.