The norm relations test for positive rank of elliptic curves

About 1 year old · traced to

Let EE be an elliptic curve over Q\mathbb{Q}, let F/QF / \mathbb{Q} be a finite Galois extension with G=Gal⁡(F/Q)G = \operatorname{Gal}(F / \mathbb{Q}), and let ρ\rho be an irreducible representation of GG. Write Q(ρ)\mathbb{Q}(\rho) for the field generated by the character values of ρ\rho, and for σ∈Gal⁡(Q(ρ)/Q)\sigma \in \operatorname{Gal}(\mathbb{Q}(\rho) / \mathbb{Q}) let ρσ\rho^\sigma denote the Galois-conjugate representation. Suppose that

(⨁σ∈Gal⁡(Q(ρ)/Q)ρσ)⊕m=(⨁iC[G/Hi])⊖(⨁jC[G/Hj′])\left( \bigoplus_{\sigma \in \operatorname{Gal}(\mathbb{Q}(\rho) / \mathbb{Q})} \rho^\sigma \right)^{\oplus m} = \left( \bigoplus_i \mathbb{C}[G / H_i] \right) \ominus \left( \bigoplus_j \mathbb{C}[G / H_j'] \right)

for some m≥1m \geq 1 and subgroups Hi,Hj′≤GH_i,H_j' \leq G. Norm relations test. If either

∏iCE/FHi∏jCE/FHj′\frac{\prod_i C_{E / F^{H_i}}}{\prod_j C_{E / F^{H_j'}}}

is not a norm from some quadratic field Q(D)⊂Q(ρ)\mathbb{Q}(\sqrt{D}) \subset \mathbb{Q}(\rho), or is not a rational square when mm is even, then EE has a point of infinite order over FF. The test is based on the conjectural properties of the Birch–Swinnerton-Dyer quotient and is known in the source to follow from the parity conjecture for twists under stated hypotheses, while its unconditional conjectural status is not resolved there.

References

Primary source

Edwina Aylward, “Tamagawa numbers and positive rank of elliptic curves”, arXiv:2504.17962 (2026).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.