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Subrings invariant under endomorphisms

Shulim Kaliman
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Abstract

Let S and R be the rings of regular functions on affine algebraic varieties over a field of characteristic 0, R be embedded as a subring in S, and F : S --> S be an endomorphism such that F(R) subset R. Suppose that every ideal of height 1 in R generates a proper ideal in S, and the spectrum of R has no selfintersection points. We show that if F is an automorphism so is F|_R : R --> R. When R and S have the same transcendence degree then the fact that F|_R is an automorphisms implies that F is an automorphism.

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Shulim Kaliman. 2002-08-09. Subrings invariant under endomorphisms. https://arxiv.org/abs/math/0208078

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