Rank classification for twin-prime elliptic curves with p congruent to 1 modulo 8

Determine the Mordell–Weil rank of the elliptic curve E_p: y^2=x(x-2)(x-p), where p and p-2 are primes and p is congruent to 1 modulo 8, establishing whether the rank is 0 or 2.

Background

For the twin-prime elliptic curve E_p, the paper records the corrected version of a conjecture attributed to Beers and formulated by Joshi. The conjectural rank is 0 when p is congruent to 7 modulo 8, 1 when p is congruent to 3 or 5 modulo 8, and either 0 or 2 when p is congruent to 1 modulo 8.

The paper proves the relevant Selmer-corank and rank conclusions in the residue classes 3, 5, and 7 modulo 8 under its stated conditional Birch–Swinnerton-Dyer input. When p is congruent to 1 modulo 8, the 2-Selmer calculation permits several possibilities, including an unresolved odd-rank case associated with a potentially divisible 2-primary Tate–Shafarevich group. Thus the p congruent to 1 modulo 8 portion of the conjectural classification remains unresolved in the paper.

References

Joshi computed its root number and formulated the following corrected version of a conjecture of Beers:

r(E_p)= \begin{cases} 0,&p\equiv7\pmod8,\ 1,&p\equiv3,5\pmod8,\ 0\text{ or }2,&p\equiv1\pmod8. \end{cases}

— On the algebraic and analytic ranks of the twin-prime elliptic curve $y^2=x(x-2)(x-p)$  (2610.09370 - Chen, 7 Oct 2026) in Section 1, Introduction and the external input, equation (1.4); revisited in Section 4, Proposition 4.1