Authors: Janusz Adamus ^1,2; Lech Adamus ³; Anders Yeo ⁴

• 1 Department of Mathematics [London, Ontario]
• 2 Polska Akademia Nauk = Polish Academy of Sciences
• 3 Faculty of Applied Mathematics [Krakow]
• 4 Singapore University of Technology and Design

We prove a sharp Meyniel-type criterion for hamiltonicity of a balanced bipartite digraph: For a≥2, a strongly connected balanced bipartite digraph D on 2a vertices is hamiltonian if d(u)+d(v)≥3a whenever uv∉A(D) and vu∉A(D). As a consequence, we obtain a sharp sufficient condition for hamiltonicity in terms of the minimal degree: a strongly connected balanced bipartite digraph D on 2a vertices is hamiltonian if δ(D)≥3a/2.