ISSN 1234-3099 (print version)
ISSN 2083-5892 (electronic version)
SCImago Journal Rank (SJR) 2018: 0.763
Rejection Rate (2017-2018): c. 84%
Discussiones Mathematicae Graph Theory 32(3) (2012)
Department of Mathematics University of Illinois Urbana, IL, 61801
Research on A-cordiality has focused on the case where A is cyclic. In this paper, we investigate V4-cordiality of many families of graphs, namely complete bipartite graphs, paths, cycles, ladders, prisms, and hypercubes. We find that all complete bipartite graphs are V4-cordial except Km,n where m,n ≡ 2(mod 4). All paths are V4-cordial except P4 and P5. All cycles are V4-cordial except C4, C5, and Ck, where k ≡ 2(mod 4). All ladders P2 [¯] Pk are V4-cordial except C4. All prisms are V4-cordial except P2 [¯] Ck, where k ≡ 2(mod 4). All hypercubes are V4-cordial, except C4.
Finally, we introduce a generalization of A-cordiality involving digraphs and quasigroups, and we show that there are infinitely many Q-cordial digraphs for every quasigroup Q.
Keywords: graph labeling, cordial graph, A-cordial, quasigroup
2010 Mathematics Subject Classification: 05C78, 05C25.
Received 30 March 2011 Revised 30 September 2011 Accepted 30 September 2011