Serre’s Uniformity Conjecture over the rational numbers

Establish that there exists a single constant C such that, for every non-CM elliptic curve E defined over the rational numbers and every prime p greater than C, the mod-p Galois representation of E is surjective.

Background

Serre’s Open Image Theorem gives a surjectivity threshold depending on the individual non-CM elliptic curve. Serre’s Uniformity Conjecture asks whether this threshold can instead be chosen uniformly for all non-CM elliptic curves over the rational numbers.

The paper uses partial classification results for mod-p images to obtain finiteness results for rational isolated j-invariants, but explicitly records that the uniformity conjecture itself remains unresolved.

References

This is still an open problem, with Theorem \ref{SerreUnifProgress} summarizing the progress to date.

On the Finiteness of Isolated $j$-invariants for $X_1(N)$  (2608.19354 - Bourdon, 19 Aug 2026) in Section 2, subsection “Galois Representations of Elliptic Curves”