Arrangements, circular arrangements and the crossing number of C7× Cn

  • Authors:
  • Jay Adamsson;R. Bruce Richter

  • Affiliations:
  • Department of Mathematics and Statistics, University of Prince Edward Island, Charlottetown PEI, Canada C1A 4P3;Department of Combinatorics and Optimization, University of Waterloo, 200 University Ave. West, Waterloo, Ont., Canada N2L 3G1

  • Venue:
  • Journal of Combinatorial Theory Series B
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

Motivated by the problem of determining the crossing number of the Cartesian product Cm × Cn of two cycles, we introduce the notion of an (m, n)-arrangement, which is a generalization of a planar drawing of Pn+1 × Cm in which the two "end cycles" are in the same face of the remaining n cycles. The main result is that every (m, n)-arrangement has at least (m - 2)n crossings. This is used to show that the crossing number of C7 × Cn is 5n, in agreement with the general conjecture that the crossing number of Cm × Cn is (m - 2)n, for 3 ≤ m ≤ n.