Vojta's inequality and rational and integral points of bounded degree on curves

Abstract

Let $C\subset C_1\times C_2$ be a curve of type $(d_1,d_2)$ in the product of the two curves $C_1$ and $C_2$. Let $\nu$ be a positive integer. We prove that if a certain inequality involving $d_1,\ d_2,\ \nu$, and the genera of the curves $C_1,\ C_2$, and $C$ is satisfied, then the set of points $\{P\in C(\bar{k})\mid[k(P):k]\leq \nu\}$ is finite for any number field $k$. We prove a similar result for integral points of bounded degree on $C$. These results are obtained as consequences of an inequality of Vojta which generalizes the Roth–Wirsing theorem to curves.