Conjectural frequency of regular twists with a rational point

Let C/QC/\mathbb Q be a genus-one hyperelliptic curve, let EE be its Jacobian, and let Fb\mathcal F_b be the twist family specified by the local data bb. Let Fb(X)={dFb:dX}\mathcal F_b(X)=\{d\in\mathcal F_b:|d|\leq X\}, let nb=dimF2Sbn_b=\dim_{\mathbb F_2}\mathcal S_b, let mb{0,1}m_b\in\{0,1\} satisfy mb1+nb(mod2)m_b\equiv1+n_b\pmod2, and let α(k)\alpha(k) be the distribution from the paper's main Selmer theorem. Regular-twist frequency conjecture. One has

limX#{dFb(X):δ(P)imδd}#Fb(X)=r=0α(2r+mb)2nb+2r+mb1.\lim_{X\rightarrow\infty}\frac{\#\{d\in\mathcal F_b(X):\delta(P)\in\operatorname{im}\delta_d\}}{\#\mathcal F_b(X)}=\sum_{r=0}^{\infty}\frac{\alpha(2r+m_b)}{2^{n_b+2r+m_b}-1}.

This is obtained by modeling the relevant nonzero Selmer element as uniformly distributed; the source presents it as a heuristic consequence of the Selmer-distribution theorem, with resolution not established.

Sources & referencesView supporting material

Primary source

Alex Bartel and Adam Morgan, “Galois module structures and the Hasse principle in twist families via the distribution of Selmer groups”, arXiv:2508.14026 (2025).

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