Points on a curve with a power on a curve

Abstract

Let $C_1,C_2\subseteq\mathbb{G}_m^N(\mathbb{C})$ be irreducible closed algebraic curves, with $N\geq 3$. Suppose $C_1$ is not contained in an algebraic subgroup of $\mathbb{G}_m^N(\mathbb{C})$ of dimension $1$ and $C_1\cup C_2$ is not contained in an algebraic subgroup of $\mathbb{G}_m^N(\mathbb{C})$ of dimension $2$. It is a conjecture that at most finitely many points $x\in C_1$ have the property that there is a positive integer $n$ such that $x^n\in C_2$ and $[n]C_1\nsubseteq C_2$, where $[n]C_1=\{x^n:x\in C_1\}$. We prove this in the case where at least one of the two curves is not defined over $\overline{\mathbb{Q}}$.