English

Hyperbolic Heron Triangles and Elliptic Curves

Number Theory 2021-02-11 v1 Metric Geometry

Abstract

We define hyperbolic Heron triangles (hyperbolic triangles with "rational" side-lengths and area) and parametrize them in two ways as rational points of certain elliptic curves. We show that there are infinitely many hyperbolic Heron triangles with one angle α\alpha and area AA for any (admissible) choice of α\alpha and AA; in particular, the congruent number problem has always infinitely many solutions in the hyperbolic setting. We also explore the question of hyperbolic triangles with a rational median and a rational area bisector (median splitting the triangle in half).

Keywords

Cite

@article{arxiv.2102.05158,
  title  = {Hyperbolic Heron Triangles and Elliptic Curves},
  author = {Matilde Lalín and Olivier Mila},
  journal= {arXiv preprint arXiv:2102.05158},
  year   = {2021}
}

Comments

16 pages

R2 v1 2026-06-23T23:00:05.489Z