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Author Srivastava, Ashish K., author.

Title Invariance of modules under automorphisms of their envelopes and covers / Ashish K. Srivastava, Askar Tuganbaev, and Pedro A. Guil Asensio
Published Cambridge, United Kingdom ; New York, NY : Cambridge University Press, 2021
©2021

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Description 1 online resource (ix, 223 pages) : illustrations
Series London Mathematical Society lecture note series ; 466
London Mathematical Society lecture note series ; 466.
Contents Cover -- Series information -- Title page -- Copyright information -- Contents -- Preface -- 1 Preliminaries -- 1.1 Basics of Ring Theory and Module Theory -- 1.2 Simple and Semisimple Modules -- 1.3 Essential and Closed Submodules -- 1.4 Prime Rings and Semiprime Rings -- 1.5 Classical Rings of Fractions and Semiprime Goldie Rings -- 1.6 Local, Semilocal and Semiperfect Rings -- 1.7 Injective and Projective Modules -- 1.8 Injective Envelope and Quasi-Injective Modules -- 1.9 Flat Modules -- 1.10 Exchange Property of Modules -- 1.11 Pure-Injective and Cotorsion Modules -- 2 Modules Invariant under Automorphisms of Envelopes -- 2.1 Introduction to Envelopes -- 2.2 Modules Invariant under Endomorphisms and Automorphisms -- 2.3 Additive Unit Structure of von Neumann Regular Rings -- 2.4 Applications of Additive Unit Structure of von Neumann Regular Rings -- 3 Structure and Properties of Modules Invariant under Automorphisms -- 3.1 Structure of Modules Invariant under Automorphisms -- 3.2 Properties of Modules Invariant under Automorphisms -- 3.3 Applications -- 3.4 Modules Invariant under Monomorphisms -- 4 Automorphism-Invariant Modules -- 4.1 Some Characterizations of Automorphism-Invariant Modules -- 4.2 Nonsingular Automorphism-Invariant Rings -- 4.3 When Is an Automorphism-Invariant Module a Quasi-Injective Module -- 4.4 Rings Whose Cyclic Modules Are Automorphism-Invariant -- 4.5 Rings Whose Each One-Sided Ideal Is Automorphism-Invariant -- 5 Modules Coinvariant under Automorphisms of their Covers -- 5.1 Structure and Properties -- 5.2 Automorphism-Coinvariant Modules -- 5.3 Dual Automorphism-Invariant Modules -- 6 Schröder-Bernstein Problem -- 6.1 Schröder-Bernstein Problem for X-Endomorphism Invariant Modules -- 6.2 Schröder-Bernstein Problem for Automorphism-Invariant Modules -- 7 Automorphism-Extendable Modules
Summary "The study of modules which are invariant under the action of certain subsets of the endomorphism ring of their injective envelope can be drawn back to the pioneering work of Johnson and Wong in which they characterized quasi-injective modules as those modules which are invariant under any endomorphism of their injective envelope. Later, Dickson and Fuller studied modules which are invariant under the group of all automorphisms of their injective envelope and proved that any indecomposable automorphism-invariant module over an F-algebra A is quasi-injective provided that F is a field with more than two elements. But after that this topic remained in dormant stage for some time until Lee and Zhou picked it up again in their paper where they called such modules auto-invariant modules. But the major breakthrough on this topic came from two papers that appeared a few months later: one of them was a paper of Er, Singh and Srivastava where they proved that the automorphism-invariant modules are precisely the pseudo-injective modules studied earlier by Teply, Jain, Clark, Huynh and others. The other one was a paper by Guil Asensio, and Srivastava where they proved that automorphism-invariant modules satisfy the exchange property and also they provide a new class of clean modules. Soon after this Guil Asensio and Srivastava extended the result of Dickson and Fuller by proving that if A is an algebra over a field F with more than two elements, then a module over A is automorphism-invariant if and only if it is quasi-injective. In 2015, in a paper published in the Israel Journal of Mathematics, Guil Asensio, Tutuncu and Srivastava laid down the foundation of general theory of modules invariant under automorphisms (resp. endomorphisms) of envelopes and covers. In this general theory of modules invariant under automorphisms (resp. endomorphisms) of envelopes and covers, we have obtained many interesting properties of such modules and found examples of some important classes of modules. When this theory is applied to some particular situations, then we obtain results that extend and simplify several results existing in the literature. For example, as a consequence of these general results, one obtains that modules invariant under automorphisms of their injective (resp., pure-injective) envelopes satisfy the full exchange property. These results extend well-known results of Warfield, Fuchs, Huisgen-Zimmermann and Zimmermann. Most importantly, this study yields us a new tool and new perspective to look at generalizations of injective, pure-injective or at-cotorsion modules. Until now most of the generalizations of injective modules were focussed on relaxing conditions on lifting of homomorphisms but this theory has opened up a whole new direction in the study of module theory"-- Provided by publisher
Bibliography Includes bibliographical references and index
Notes Description based on online resource; title from digital title page (viewed on April 16, 2021)
Subject Modules (Algebra)
Módulos (Álgebra)
Modules (Algebra)
Mòduls (Àlgebra)
Genre/Form Llibres electrònics.
Form Electronic book
Author Tuganbaev, Askar A., author.
Guil Asensio, Pedro A., 1964- author.
LC no. 2020058390
ISBN 9781108954563
1108954561
9781108960366
1108960367