Modules whose nonzero finitely generated submodules are dense

Document Type : Research Paper

Author

Department of Mathematics, Mobarakeh Branch, Islamic Azad University, Isfahan, Iran,

Abstract

Let R be a commutative ring with identity and M be a unitary R-module. First, we study multiplication R-modules M where R is a one dimensional Noetherian ring or M is a finitely generated R-module. In fact, it is proved that if M is a multiplication R-module over a one dimensional Noetherian ring R, then MI for some invertible ideal I of R or M is cyclic. Also, a multiplication R-module M is finitely generated if and only if M contains a finitely generated submodule N such that AnnR(N)=AnnR(M). A submodule N of M is called dense in M, if M=φφ(N) where φ runs over all the R-homomorphisms from N into M and R-module M is called a weak π-module if every non-zero finitely generated submodule is dense in M. It is shown that a faithful multiplication module over an integral domain R is a weak π-module if and only if it is a  Prufer prime module.

Keywords


[1] M.M. Ali and D.J. Smith, Some remarks on multiplication and projective modules, Communications in Algebra, Vol. 32 No. 10 (2004), pp. 3897–3909.
[2] M. Alkan and Y. Tras, On invertible and dense submodules, Communications in Algebra, Vol. 32 No. 10 (2004), pp. 3911–3919.
[3] A. Azizi, Principal ideal multiplication modules, Algebra Colloquium, Vol. 15 No. 04 (2008), pp. 637–648.
[4] A. Barnard, Multiplication modules, Journal of Algebra, Vol. 71 (1981), pp. 174–178.
[5] M. Behboodi, On prime modules and dense submodules, Journal of commutative Algebra, Vol. 4 No. 4 (2012), pp. 479–488.
[6] Z.A. El-Bast and P.F. Smith, Multiplication modules, Communications in Algebra, Vol. 16 (1988), pp. 755–799.
[7] G.D. Findlay and J. Lambek, A generalized ring of quotients, I, II, Canadian Mathematical Bulletin, Vol. 1 (1958), pp. 77–85, 155–167.
[8] A. Hajikarimi and A.R. Naghipour, A note on monoform modules, Bulletin of the Korean Mathematical Society, Vol. 56 No. 2 (2019), pp. 505–514.
[9] A.G. Naoum and F.G. Al-Alwan, Dense submodules of multiplication modules, Communications in Algebra, Vol. 24 No. 2 (1996), pp. 413–424.
[10] A.G. Naoum and F.G. Al-Alwan, Dedekind modules, Communications in Algebra, Vol. 24 No. 2 (1996), pp. 397–412.
[11] W.K. Nicholson, J.K. Park and M.F. Yousif, Principally quasi-injective modules, Communications in Algebra, Vol. 27 No. 4 (1999), pp. 1683–1693.
[12] P.F. Smith, Some remarks on multiplication modules, Archiv der Mathematik, Vol. 50 (1988), pp. 223–235.