Question:

A simple graph G on n vertices (n ≥2) is drawn in the plane.

Last updated: 8/9/2022

A simple graph G on n vertices (n ≥2) is drawn in the plane.

A simple graph G on n vertices (n ≥2) is drawn in the plane. Prove that if every edge crosses at most one another edge, then the number of edges in G does not exceed 4n - 8.