Graphs and Matroids Seminar

Title: Gaps in the crossing numbers of drawings of the complete graph

Abstract: In the late 1990’s, a 5-author manuscript circulated proving the existence of intervals of integers that connot occur as the crossing number of a “good” drawing of the complete graph.  With Alan Arroyo and Matt Sullivan, we have revived this research and realized it leads to an interesting parity problem in set theory.  One instance of this problem can be treated exactly as in the original manuscript.