On the section conjecture and Brauer-Severi varieties

Abstract

J. Stix proved that a curve of positive genus over $\mathbb{Q}$ which maps to a non-trivial Brauer-Severi variety satisfies the section conjecture. We prove that, if $X$ is a curve of positive genus over a number field $k$ and the Weil restriction $R_{k/\mathbb{Q}}X$ admits a rational map to a non-trivial Brauer-Severi variety, then $X$ satisfies the section conjecture. As a consequence, if $X$ maps to a Brauer-Severi variety $P$ such that the corestriction ${\mathrm{cor}}_{k/\mathbb{Q}}([P])\in \mathrm{Br}(\mathbb{Q})$ is non-trivial, then $X$ satisfies the section conjecture.