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arXiv · 1203.6294

Weil's Galois Descent Theorem from a computational point of view

Rubén A. Hidalgo·Sebastián Reyes-Carocca
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Abstract

Let ${\mathcal L}/{\mathcal K}$ be a finite Galois extension and let $X$ be an affine algebraic variety defined over ${\mathcal L}$. Weil's Galois descent theorem provides necessary and sufficient conditions for $X$ to be definable over ${\mathcal K}$, that is, for the existence of an algebraic variety $Y$ defined over ${\mathcal K}$ together with a birational isomorphism $R:X \to Y$ defined over ${\mathcal L}$. Weil's proof does not provide a method to construct the birational isomorphism $R.$ The aim of this paper is to give an explicit construction of $R$.

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Rubén A. Hidalgo, Sebastián Reyes-Carocca. 2012-03-28. Weil's Galois Descent Theorem from a computational point of view. https://doi.org/10.1090/conm%2F766%2F15383

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