Timo Keller

collaborators

2 papers

math.NT2025

Rational points on $X_{0} (N)^{*}$ when $N$ is non-squarefree

Sachi Hashimoto, Timo Keller, Samuel Le Fourn

Let $N$ be a non-squarefree integer such that the quotient $X_{0} (N)^{*}$ of the modular curve $X_{0} (N)$ by the full group of Atkin-Lehner involutions has positive genus. Elkies conject…

math.NT2025

Towards a classification of isolated $j$ -invariants

Abbey Bourdon, Sachi Hashimoto, Timo Keller +5

We develop an algorithm to test whether a non-CM elliptic curve $E / Q$ gives rise to an isolated point of any degree on any modular curve of the form $X_{1} (N)$ . This builds…

Rational points on X0​(N)∗ when N is non-squarefree

Towards a classification of isolated j-invariants

Rational points on $X_{0} (N)^{*}$ when $N$ is non-squarefree

Towards a classification of isolated $j$ -invariants