A census of 4-valent half-arc-transitive graphs and arc-transitive digraphs of valence twoPotočnik, Primož (Avtor) Spiga, Pablo (Avtor) Verret, Gabriel (Avtor) graphsdigraphsedge-transitivevertex-transitivearc-transitivehalf arc-transitiveA complete list of all connected arc-transitive asymmetric digraphs of in-valence and out-valence 2 on up to 1000 vertices is presented. As a byproduct, a complete list of all connected 4-valent graphs admitting a half-arc-transitive group of automorphisms on up to 1000 vertices is obtained. Several graph-theoretical properties of the elements of our census are calculated and discussed.20152021-12-31 00:36:55Neznano17612UDK: 519.17:512.542ISSN pri članku: 1855-3966COBISS.SI-ID: 1536989124sl