Intersection number (graph theory)

In graph theory, the term "intersection number" can refer to different concepts depending on the context. However, it is most commonly associated with two specific usages: 1. **Intersection Number of a Graph**: This is the minimum number of intersections in a planar drawing of a graph. A graph is drawn in the plane such that its edges do not intersect except at their endpoints. The intersection number can be an important characteristic when studying the embedding of graphs on surfaces or in understanding their topological properties.