Disjoint edges in geometric graphs

N. Alon, P. Erdös
1989 Discrete & Computational Geometry  
Answering an old question in combinatorial geometry, we show that any configuration consisting of a set V of n points in general position in the plane and a set of 6n -5 closed straight line segments whose endpoints lie in V, contains three pairwise disjoint line segments.
doi:10.1007/bf02187731 fatcat:g35gj4japjanrp7dtnefkhgnve