Keywords: domination; double domination; total domination; double total domination; planar graph; triangulated disc
Summary: Let $G$ be a $3$-connected triangulated disc of order $n$ with the boundary cycle $C$ of the outer face of $G$. Tokunaga (2013) conjectured that $G$ has a dominating set of cardinality at most $\frac 14(n+2)$. This conjecture is proved in Tokunaga (2020) for $G-C$ being a tree. In this paper we prove the above conjecture for $G-C$ being a unicyclic graph. We also deduce some bounds for the double domination number, total domination number and double total domination number in triangulated discs.
[2] Blidia, M., Chellali, M., Haynes, T. W.: Characterizations of trees with equal paired and double domination numbers. Discrete Math. 306 (2006), 1840-1845. DOI 10.1016/j.disc.2006.03.061 | MR 2251565 | Zbl 1100.05068
[6] Fernau, H., Rodríguez-Velázquez, J. A., Sigarreta, J. M.: Global powerful $r$-alliances and total $k$-domination in graphs. Util. Math. 98 (2015), 127-147. MR 3410888 | Zbl 1343.05115
[8] Harary, F., Haynes, T. W.: Double domination in graphs. Ars Comb. 55 (2000), 201-213. MR 1755232 | Zbl 0993.05104
[9] Haynes, T. W., Hedetniemi, S. T., Slater, P. J.: Fundamentals of Domination in Graphs. Pure and Applied Mathematics, Marcel Dekker 208. Marcel Dekker, New York (1998). DOI 10.1201/9781482246582 | MR 1605684 | Zbl 0890.05002
[12] Henning, M. A., Yeo, A.: Strong transversals in hypergraphs and double total domination in graphs. SIAM J. Discrete Math. 24 (2010), 1336-1355. DOI 10.1137/090777001 | MR 2735927 | Zbl 1221.05254