A Chvátal--Erdős type condition for supereulerian digraphs with ${\alpha }_2=4$

Zirui Liu, Jin Yan, Jia Zhou

A digraph is \textbf{supereulerian} if it contains a spanning closed trail. Let ${\alpha }_2(D)$ denote the maximum cardinality of a vertex set inducing no 2-cycle. In this paper, we chara…