Degrees of isogenies over prime degree number fields of non-CM elliptic curves with rational $j$-invariant

Abstract

We determine all possible degrees of cyclic isogenies of non-CM elliptic curves with rational $j$-invariant over number fields of degree $p$, where $p$ is an odd prime. The question had been answered for $p=2$, so this paper completes the classification in case when the degree of the number field is prime.