English

The relationship between face cuboids and elliptic curves

Number Theory 2024-07-16 v1

Abstract

A rational face cuboid is a cuboid that all of edges, two of three face diagonals and space diagonal have rational lengths. E1,s:y2=x(x(2s)2)(x+(s21)2) E_{1,s}: y^2=x(x-(2s)^2)(x+(s^2-1)^2) for a rational number s0,±1s \neq 0, \pm 1, and define A~\tilde{A} consisting of all pairs of a rational number ss and a non-torsion rational point (α,β)E1,s(Q)(\alpha, \beta ) \in E_{1,s}(\mathbb{Q}). We construct a surjective map from A~\tilde{A} to the set F\mathscr{F} of equivalence classes of rational face cuboids, and prove that this map is a 32:132:1-map. In this way, we show that the set F\mathscr{F} has infinite elements. Also, we prove that there are infinitely many sQ{0,±1}s \in \mathbb{Q} \setminus \{ 0,\pm 1 \} with rankE1,s(Q)>0\mathrm{rank} E_{1,s} (\mathbb{Q})>0. In this proof, we construct pairs of ss and (α,β)E1,s(Q)(\alpha, \beta) \in E_{1,s} (\mathbb{Q}) which are not parametric solutions.

Keywords

Cite

@article{arxiv.2407.09825,
  title  = {The relationship between face cuboids and elliptic curves},
  author = {Takumi Yoshida},
  journal= {arXiv preprint arXiv:2407.09825},
  year   = {2024}
}

Comments

10 pages

R2 v1 2026-06-28T17:39:37.467Z