Joey M. van Langen | Searcharxiv

arXiv2023

Explicitly bounding perfect powers in elliptic divisibility sequences

In this paper we consider elliptic divisibility sequences generated by a point on an elliptic curve over $\mathbb{Q}$ with $j$-invariant $1728$ given by an integral short Weierstrass equation. For several different such elliptic divisibility sequences, we determine explicitly a finite set of primes such that for all primes $l$ outside this set, the elliptic divisibility sequence contains no $l$-th powers. Our approach uses, amongst other ingredients, the modular method for $\mathbb{Q}$-curves. The corresponding explicit computations fit into a general computational framework for $\mathbb{Q}$-curves, for which they provide illustrative examples.

math.NT↗

arXiv2020

On the sum of fourth powers in arithmetic progression

We prove that the equation ${ (x - y)^4 + x^4 + (x + y)^4 = z^n }$ has no integer solutions ${ x, y, z}$ with ${ \gcd(x, y) = 1 }$ for all integers ${ n > 1 }$. We mainly use a modular approach with two Frey ${ \mathbb{Q} }$-curves defined over the field ${ \mathbb{Q}( \sqrt{30} ) }$.

math.NT↗