A note on antimagic orientations of even regular graphs

Motivated by the conjecture of Hartsfield and Ringel on antimagic labellings of undirected graphs, Hefetz, Maze, and Schwartz initiated the study of antimagic labellings of digraphs in 2010. Very recently, it has been conjectured in Li et al. (2019) that every graph admits an antimagic orientation, which is a strengthening of an earlier conjecture of Hefetz, Mutze and Schwartz. In this paper, we prove that every 2d-regular graph (not necessarily connected) admits an antimagic orientation, where d >= 2. Together with known results, our main result implies that the above-mentioned conjecture is true for all regular graphs. (C) 2019 Elsevier B.V. All rights reserved.