The Elementary Theory of the Frobenius Automorphisms

A Frobenius difference field is an algebraically closed field of characteristic $p>0$, enriched with a symbol for $x \mapsto x^{p^m}$. We study a sentence or formula in the language of fields with a distinguished automorphism, interpreted in Frobenius difference fields with $p$ or $m$ tending...

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Main Author: Hrushovski, E
Format: Journal article
Published: 2004
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author Hrushovski, E
author_facet Hrushovski, E
author_sort Hrushovski, E
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description A Frobenius difference field is an algebraically closed field of characteristic $p>0$, enriched with a symbol for $x \mapsto x^{p^m}$. We study a sentence or formula in the language of fields with a distinguished automorphism, interpreted in Frobenius difference fields with $p$ or $m$ tending to infinity. In particular, a decision procedure is found to determine when a sentence is true in almost every Frobenius difference field. This generalizes Cebotarev's density theorem and Weil's Riemann hypothesis for curves (both in qualitative versions), but hinges on a result going slightly beyond the latter. The setting for the proof is the geometry of difference varieties of transformal dimension zero; these generalize algebraic varieties, and are shown to have a rich structure, only partly explicated here. Some applications are given, in particular to finite simple groups, and to the Jacobi bound for difference equations.
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spelling oxford-uuid:f8341253-3d79-4b1b-92e9-7294026decff2022-03-27T12:48:31ZThe Elementary Theory of the Frobenius AutomorphismsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f8341253-3d79-4b1b-92e9-7294026decffSymplectic Elements at Oxford2004Hrushovski, EA Frobenius difference field is an algebraically closed field of characteristic $p>0$, enriched with a symbol for $x \mapsto x^{p^m}$. We study a sentence or formula in the language of fields with a distinguished automorphism, interpreted in Frobenius difference fields with $p$ or $m$ tending to infinity. In particular, a decision procedure is found to determine when a sentence is true in almost every Frobenius difference field. This generalizes Cebotarev's density theorem and Weil's Riemann hypothesis for curves (both in qualitative versions), but hinges on a result going slightly beyond the latter. The setting for the proof is the geometry of difference varieties of transformal dimension zero; these generalize algebraic varieties, and are shown to have a rich structure, only partly explicated here. Some applications are given, in particular to finite simple groups, and to the Jacobi bound for difference equations.
spellingShingle Hrushovski, E
The Elementary Theory of the Frobenius Automorphisms
title The Elementary Theory of the Frobenius Automorphisms
title_full The Elementary Theory of the Frobenius Automorphisms
title_fullStr The Elementary Theory of the Frobenius Automorphisms
title_full_unstemmed The Elementary Theory of the Frobenius Automorphisms
title_short The Elementary Theory of the Frobenius Automorphisms
title_sort elementary theory of the frobenius automorphisms
work_keys_str_mv AT hrushovskie theelementarytheoryofthefrobeniusautomorphisms
AT hrushovskie elementarytheoryofthefrobeniusautomorphisms