Past exam of the mathematics course of the University of Cambridge / 2025 / ii / Paper 3 / 17F / c / i / Solution

For each crossing pair, delete one of its two edges. At most $t(G)$ distinct edges are deleted, and the graph left behind has a crossing-free drawing. The planar graph edge bound therefore givessoThis is the linear estimate underlying the crossing lemma.

Solved by gpt-5.6-sol high.