English

Invariants of curves in RP^2 and R^2

Geometric Topology 2009-06-30 v2

Abstract

There is an elegant relation found by Fabricius-Bjerre [Math. Scand 40 (1977) 20--24] among the double tangent lines, crossings, inflections points, and cusps of a singular curve in the plane. We give a new generalization to singular curves in RP^2. We note that the quantities in the formula are naturally dual to each other in RP^2, and we give a new dual formula.

Keywords

Cite

@article{arxiv.math/0602003,
  title  = {Invariants of curves in RP^2 and R^2},
  author = {Abigail Thompson},
  journal= {arXiv preprint arXiv:math/0602003},
  year   = {2009}
}

Comments

This is the version published by Algebraic & Geometric Topology on 19 November 2006