On the birational section conjecture with local conditions
Abstract
A birationally liftable Galois section s of a hyperbolic curve X/k over a number field k yields an adelic point x(s) in the smooth completion of X. We show that x(s) is X-integral outside a set of places of Dirichlet density 0, or s is cuspidal. The proof relies on -quotients of for some open U of X. If k is totally real or imaginary quadratic, we prove that all birationally adelic, non-cuspidal Galois sections come from rational points as predicted by the section conjecture of anabelian geometry. As an aside we also obtain a strong approximation result for rational points on hyperbolic curves over Q or imaginary quadratic fields.
Cite
@article{arxiv.1203.3236,
title = {On the birational section conjecture with local conditions},
author = {Jakob Stix},
journal= {arXiv preprint arXiv:1203.3236},
year = {2015}
}
Comments
Theorem C (and Section 7) of the original version have been deleted due to a gap in the proof. This is the journal version