Points of Low Degree on Smooth Plane Curves

Abstract

The purpose of this note is to provide some applications of Faltings' recent proof of S. Lang's conjecture to smooth plane curves. Let $C$ be a smooth plane curve defined by an equation of degree $d$ with integral coefficients. We show that for $d\ge 7$, the curve $C$ has only finitely many points whose field of definition has degree $\le d-2$ over $Q$, and that for $d\ge 8$, all but finitely many points of $C$ whose field of definition has degree $\le d-1$ over $Q$ arise as points of intersection of rational lines through rational points of $C$.