Cycles and paths of many lengths in bipartite digraphs
Let D denote a bipartite digraph in which each node has indegree and outdegree at least r. The authors show, among other things, that if \(k\leq 2r-1\) then D contains a cycle of length 2k unless D belongs to a class of exceptional graphs which are characterized.
scientific article; zbMATH DE number 4170936
scientific article