English

An euclidean affine invariant of quadrilaterals

General Mathematics 2022-02-14 v3

Abstract

A certain real number, depending on two neighbouring sides of a quadrilateral and the diagonal meeting these two sides at their common point, is shown to be invariant under affinity. As an application we demonstrate a nice formula for the area of a finite sector at centre of a planar quadric with point symmetry.

Keywords

Cite

@article{arxiv.1004.2829,
  title  = {An euclidean affine invariant of quadrilaterals},
  author = {Helmut Kahl},
  journal= {arXiv preprint arXiv:1004.2829},
  year   = {2022}
}

Comments

deprecated by arXiv:1007.0152