Integers that are sums of two cubes in the cyclotomic ${\mathbb{Z}}_p$-extension

Abstract

Let $n$ be a cubefree natural number and $p\ge 5$ be a prime number. Assume that $n$ is not expressible as a sum of the form $x^3+y^3$, where $x,y\in \mathbb{Q}$. In this note, we study the solutions (or lack thereof) to the equation $n=x^3+y^3$, where $x$ and $y$ belong to the cyclotomic ${\mathbb{Z}}_p$-extension of $\mathbb{Q}$. As an application, consider the case when $n$ is not a sum of rational cubes. Then, we prove that $n$ cannot be a sum of two cubes in certain large families of prime cyclic extensions of $\mathbb{Q}$.

Accepted for publication in the Tohoku Math J

References in corpus (3)

• On Asymptotic Fermat over ${\mathbb{Z}}_p$ extensions of $\mathbb{Q}$
• Arithmetic statistics and diophantine stability for elliptic curves
• Hilbert's tenth problem in Anticyclotomic towers of number fields