English

On a necessary and sufficient cyclicity condition for a quadrilateral

General Mathematics 2007-05-23 v1 Commutative Algebra Metric Geometry

Abstract

A convex quadrilateral with sides a,b,c,d, and diagonals p,q is cyclic iff abp-bcq+cdp-daq=0. This condition, in spite of its simplicity, appears to be unnoted and unexpectedly proof-resilient. We employ advanced methods of computer algebra and nonlinear analysis.

Keywords

Cite

@article{arxiv.math/0410234,
  title  = {On a necessary and sufficient cyclicity condition for a quadrilateral},
  author = {Sergey Sadov},
  journal= {arXiv preprint arXiv:math/0410234},
  year   = {2007}
}

Comments

28 pp, 2 figures, A4 paper, in Russian

R2 v1 2026-07-22T17:10:59.611Z