2018/01/16 by Darbinyan, Samvel Kh.
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.1801.05177
We prove that a strongly connected balanced bipartite directed graph of order 2a≥ 6 with partite sets X and Y contains cycles of every length 2, 4, … , 2a, provided d(x)+d(y)≥ 3a for every pair of vertices x, y either both in X or both in Y.