Pop proved that a smooth curve C over an ample field K that has a K-rational
point has |K| many K-rational points. We strengthen this result by showing that
there are |K| many K-rational points that do not lie in a given proper
subfield, even after applying a rational map. As a consequence we gain insight
into the structure of existentially definable subsets of ample fields. In
particular, we prove that a perfect ample field has no existentially definable
proper infinite subfields.
Publié le : 2008-11-18
Classification:
Mathematics - Algebraic Geometry,
Mathematics - Logic,
Mathematics - Number Theory,
12E30,
14G05,
12F99,
03C60
@article{0811.2895,
author = {Fehm, Arno},
title = {Subfields of ample fields I. Rational maps and definability},
journal = {arXiv},
volume = {2008},
number = {0},
year = {2008},
language = {en},
url = {http://dml.mathdoc.fr/item/0811.2895}
}
Fehm, Arno. Subfields of ample fields I. Rational maps and definability. arXiv, Tome 2008 (2008) no. 0, . http://gdmltest.u-ga.fr/item/0811.2895/