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Separable criteria for $ G$-diagrams over commutative rings


Author: Charles Winfred Roark
Journal: Proc. Amer. Math. Soc. 63 (1977), 1-5
MSC: Primary 16A74; Secondary 16A16, 13B05
DOI: https://doi.org/10.1090/S0002-9939-1977-0437609-2
MathSciNet review: 0437609
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Abstract: Let S be a commutative, separable algebra over the commutative ring R and finitely generated and projective as an R-module. Suppose G is a group of ring automorphisms of S stabilizing R setwise. It is shown that for the ring of invariants $ {S^G}$ to be a strongly separable extension of $ {R^G}$ it is necessary that $ R \cdot {S^G}$ be R-separable; and it is shown that this condition is sufficient when R and S are finitely generated algebras over an algebraically closed field and G is a linearly reductive algebraic group acting rationally on S.


References [Enhancements On Off] (What's this?)

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Additional Information

DOI: https://doi.org/10.1090/S0002-9939-1977-0437609-2
Keywords: Separable algebra, Galois extension, linearly reductive algebraic group, rational G-module, G-ergodic
Article copyright: © Copyright 1977 American Mathematical Society

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