English

Simple wedge points

Combinatorics 2012-09-10 v2

Abstract

Let V be a finite set of points in the plane, not contained in a line. Assume |V| = n is an odd number, and |L \cap V| \leq 3 for every line L which is spanned by V. We prove that every simple line L_{a,b} in V creates a simple wedge (i.e., a triple {a, b, c} \subseteq V such that L_{a,b} and L_{a,c} are simple lines). We also show that both restrictions on V (namely |V| is odd and |L \cap V| \leq 3) are needed. We conjecture, further, that if |V | = n is an odd number then V contains a simple wedge, even if V is not 3-bounded. We introduce a method for proving this, which gives (in this paper) partial results.

Keywords

Cite

@article{arxiv.1007.1375,
  title  = {Simple wedge points},
  author = {Shimon Garti},
  journal= {arXiv preprint arXiv:1007.1375},
  year   = {2012}
}

Comments

10 pages

R2 v1 2026-06-21T15:45:59.041Z