The Noetherian dimension of modules versus their α-small shortness

Document Type : Research Paper

Author

Department of Mathematics, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

In this article, we first consider concept of small Noetherian dimension of a module, which is dual to the small krull dimension, denoted by sndimA, and defined to be the codeviation of the poset of the small submodules of A. We prove that if an R-module A with finite hollow dimension, has small Noetherian dimension, then A has Noetherian dimension and sndimAndimAsndimA+1. Last we introduce the concept of α-small short modules, i.e., for each small submodule S of A, either ndimSα or sndimASα and α is the least ordinal number with this property and by using this concept, we extend some of the basic results of short modules to α-small short modules. In particular, we prove that if A is an α-small short module, then it has small Noetherian dimension and sndimA=α or sndimA=α+1. Consequently, we show that if A is an α-small short module with finite hollow dimension, then αndimAα+2.

Keywords


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