Hamiltonian tournaments and Gorenstein rings

  • Authors:
  • Hidefumi Ohsugi;Takayuki Hibi

  • Affiliations:
  • Department of Mathematics, Rikkyo University, Nishi-lkebukuro, Tokyo 171-8501, Japan;Department of Pure and Applied Mathematics, Graduate School of Information Science and Technology, Osaka University, Toyonaka, Osaka 560-0043, Japan

  • Venue:
  • European Journal of Combinatorics
  • Year:
  • 2002

Quantified Score

Hi-index 0.00

Visualization

Abstract

Let Gn be the complete graph on the vertex set [n] = {1, 2, ..., n} and ω an orientation of Gn, i,e., ω is an assignment of a direction i → j of each edge {i, j} of Gn. Let eq denote the qth unit coordinate vector of Rn. Write P(Gn;ω) ⊂ Rn for the convex hull of the (n 2) points ei - ej, where i → j is the direction of the edge {i, j} in the orientation ω. It will be proved that, for n ≥ 5, the Ehrhart ring of the convex polytope P(Gn;ω) is Gorenstein if and only if (Gn;ω) possesses a Hamiltonian cycle, i.e., a directed cycle of length n.