Crossing Number (Graph Theory)

In graph theory, the crossing number of a graph G is the lowest number of edge crossings achievable in a plane drawing of G; a graph is planar exactly when its crossing number is zero. Determining the crossing number matters in graph drawing, since studies of how people read diagrams have shown that drawings with fewer crossings are easier to understand. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/