Crossing Numbers and Hard Erdos Problems in Discrete Geometry
AbstractWe show that an old but not well-known lower bound for the crossing number of a graph yields short proofs for a number of bounds in discrete plane geometry which were considered hard before: the number of incidences among points and lines, the maximum number of unit distances among n points, the minimum number of distinct distances among n points. (Received August 30 1995)(Revised November 17 1995) |