projective maximal submodules of extending regular modules

Projective maximal submodules of extending regular modules

We show  that a projective maximal submodule of afinitely generated, regular, extending module is a directsummand. Hence, every finitely generated, regular, extendingmodule with projective maximal submodules is semisimple. As aconsequence, we observe that every regular, hereditary, extendingmodule is semisimple. This generalizes and simplifies a result of  Dung and   Smith. As another consequen...

Maximal Submodules and the Second Loewy Layer of Standard Modules

The paper begins in §1 with a foundational discussion of a new notion, that of a semistandard filtration in a highest weight category. The main result is Theorem 1, which says that “multiplicities” of standard modules in such filtration are well-defined. In §2, we specialize to the case of semistandard filtrations of maximal submodules of standard modules. The main result is Theorem 2, which un...

Submodules of Secondary Modules

Pure Submodules of Multiplication Modules

The purpose of this paper is to investigate pure submodules of multiplication modules. We introduce the concept of idempotent submodule generalizing idempotent ideal. We show that a submodule of a multiplication module with pure annihilator is pure if and only if it is multiplication and idempotent. Various properties and characterizations of pure submodules of multiplication modules are consid...

Computation of maximal reachability submodules

A new and conceptually simple procedure is derived for the computation of the maximal reachability submodule of a given submodule of the state space of a linear discrete time system over a Noethenian ring R. The procedure is effective if R is effective and if kernels and intersections can be computed. The procedure is compared with a rather different procedure by Assan e.a. published recently.

ON PROJECTIVE L- MODULES

The concepts of free modules, projective modules, injective modules and the likeform an important area in module theory. The notion of free fuzzy modules was introducedby Muganda as an extension of free modules in the fuzzy context. Zahedi and Ameriintroduced the concept of projective and injective L-modules. In this paper we give analternate definition for projective L-modules. We prove that e...