English

Rational distance sets on a parabola using Pythagorean triplets

Number Theory 2022-12-09 v1 Algebraic Geometry Combinatorics

Abstract

We study NN-point rational distance sets (RDS(N)\textrm{RDS}(N)) on the parabola y=x2y=x^2. Previous approaches to the problem include efforts made using elliptic curves and diophantine chains, with successful analysis for N4N\leq 4. We extend the analysis for arbitrary NN by establishing a correspondence between RDS(N)\textrm{RDS}(N)s and Pythagorean triplets. Our main result gives sufficient and necessary conditions for the existence and nature of the RDS(N)\textrm{RDS}(N)s for arbitrary NN. Our approach also leads to an efficient computational algorithm to construct new RDS(N)\textrm{RDS}(N)s, and we provide multiple new examples of RDS(N)\textrm{RDS}(N)s for four and five points. The correspondence with Pythagorean triplets also helps to study the density of the solutions and we reproduce density results for N=2N=2 and 33.

Keywords

Cite

@article{arxiv.2212.04434,
  title  = {Rational distance sets on a parabola using Pythagorean triplets},
  author = {Sayak Bhattacharjee and Divyam Jain},
  journal= {arXiv preprint arXiv:2212.04434},
  year   = {2022}
}

Comments

18 pages, 1 figure, 3 tables

R2 v1 2026-06-28T07:26:29.847Z