English

Points defining triangles with distinct circumradii

Metric Geometry 2015-10-13 v1 Computational Geometry

Abstract

Paul Erdos asked if, among sufficiently many points in general position, there are always kk points such that all the circles through 33 of these kk points have different radii. He later proved that this is indeed the case. However, he overlooked a non-trivial case in his proof. In this note we deal with this case using B\'ezout's Theorem on the number of intersection points of two curves and obtain a polynomial bound for the needed number of points.

Keywords

Cite

@article{arxiv.1402.6276,
  title  = {Points defining triangles with distinct circumradii},
  author = {Leonardo Martínez and Edgardo Roldán-Pensado},
  journal= {arXiv preprint arXiv:1402.6276},
  year   = {2015}
}
R2 v1 2026-06-22T03:15:35.580Z