CHARACTERIZATION OF AUTOMORPHISM-INVARIANT MODULE BY ITS INJECTIVITY

Let M be a module over ring R. An Injective hull of M, denoted by E(M), is an injective module which contain M as its essential submodule. If M is invariant under any automorphism of E(M), then M is called an automorphism- invariant module. Direct summand of an automorphism-invariant module is auto...

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Bibliographic Details
Main Author: Syafrian Putri, Inne
Format: Theses
Language:Indonesia
Subjects:
Online Access:https://digilib.itb.ac.id/gdl/view/34872
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Institution: Institut Teknologi Bandung
Language: Indonesia
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Summary:Let M be a module over ring R. An Injective hull of M, denoted by E(M), is an injective module which contain M as its essential submodule. If M is invariant under any automorphism of E(M), then M is called an automorphism- invariant module. Direct summand of an automorphism-invariant module is automorphism-invariant, and if the direct sum M1 o M2 is automorphism-invariant then M1 dan M2 are relatively injective. The sufficient and neces- sary condition for a module M to be automorphism-invariant is every isomor-phism between two essential submodules of M extend to an endomorphism of M. This gives a result that every pseudo-injective module is automorphism-invariant. In this thesis showed that the module M is automorphism-invariant if and only if M pseudo-injective.