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On the Galois Theory of Commutative Rings II: Automorphisms induced in Residue Rings

Published online by Cambridge University Press:  20 November 2018

Carl Faith*
Affiliation:
Rutgers University, New Brunswick, New Jersey
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Let G be a group of automorphisms of a commutative ring K, and let KG denote the Galois subring consisting of all elements left fixed by every g in G. An ideal M is G-stable, or G-invariant, provided that g(x) lies in M for every x in M, that is, g(M)M, for every g in G. Then, every g in G induces an automorphism in the residue ring , and if is the group consisting of all , trivially

1

When the inclusion (1) is strict, then G is said to be cleft at M, or by M, and otherwise G is uncleft at (by) M. When G is cleft at all ideals except 0, then G is cleft, and uncleft otherwise.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1987

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