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On elementary equivalence, isomorphism and isogeny of arithmetic function fields

Pete L. Clark
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Abstract

Motivated by recent work of Florian Pop, we study the connections between three notions of equivalence of function fields: isomorphism, elementary equivalence, and the condition that each of a pair of fields can be embedded in the other, which we call isogeny. Some of our results are purely geometric: we give an isogeny classification of Severi-Brauer varieties and of quadric surfaces. These results are applied to deduce new instances of "elementary equivalence implies isomorphism": for all genus zero curves over a number field, and for certain genus one curves over a number field, including some which are not elliptic curves.

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Pete L. Clark. 2004-06-08. On elementary equivalence, isomorphism and isogeny of arithmetic function fields. https://arxiv.org/abs/math/0406133

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