English

Real circles tangent to 3 conics

Algebraic Geometry 2025-05-07 v1

Abstract

In this paper we study circles tangent to conics. We show there are generically 184184 complex circles tangent to three conics in the plane and we characterize the real discriminant of the corresponding polynomial system. We give an explicit example of 33 conics with 136136 real circles tangent to them. We conjecture that 136 is the maximal number of real circles. Furthermore, we implement a hill-climbing algorithm to find instances of conics with many real circles, and we introduce a machine learning model that, given three real conics, predicts the number of circles tangent to these three conics.

Keywords

Cite

@article{arxiv.2211.06876,
  title  = {Real circles tangent to 3 conics},
  author = {Paul Breiding and Julia Lindberg and Wern Juin Gabriel Ong and Linus Sommer},
  journal= {arXiv preprint arXiv:2211.06876},
  year   = {2025}
}

Comments

22 pages

R2 v1 2026-06-28T05:44:58.865Z