Improvement on the Decay of Crossing Numbers

We prove that the crossing number of a graph decays in a " continuous fashion " in the following sense. For any ε > 0 there is a δ > 0 such that for a sufficiently large n, every graph G with n vertices and m ≥ n 1+ε edges, has a subgraph G ′ of at most (1 − δ)m edges and crossing number at least (1 − ε)cr(G). This generalizes the result of J. Fox and Cs. Tóth.