A conjecture on Galois groups and large fields

Abstract

Let $p$ be a prime number and let $K$ be a field such that $p$ is prime to the absolute Galois group $\operatorname{Gal}(K)$, in the sense that $p$ does not divide the degree of any finite Galois extension of $K$. We conjecture that $K$ is large in the sense of Pop: any smooth algebraic curve $C$ over $K$ with a $K$-rational point has infinitely many $K$-rational points. This conjecture would have some consequences in mathematical logic. For instance, it would imply the expected classification of stable fields of positive characteristic. We give some weak evidence for this conjecture. Specifically, suppose that $K$ is a perfect field and $\operatorname{Gal}(K)$ is prime to $p$. Then every abelian variety $A$ over $K$ has Zariski dense $K$-rational points, and if $C$ is a smooth curve of genus less than $7-p$ with at least one $K$-rational point, then $C$ has infinitely many $K$-rational points.