For a graph G, we define the lower bipartite number LB(G) as the minimum order of a maximal induced bipartite subgraph of G. We study the parameter, and the related parameter bipartite domination, providing bounds both in general graphs and in some graph families. For example, we show that there are arbitrarily large 4-connected planar graphs G with LB(G) = 4 but a 5-connected planar graph has linear LB(G). We also show that if G is a maximal outerplanar graph of order n, then LB(G) lies between (n + 2)/3 and 2 n/3, and these bounds are sharp.
Bachstein, A., Goddard, W., and Henning, M. A. Bipartite domination in graphs. Math. Pannon. (N.S.) 28 (2022), 118–126.
Byskov, J. M., Madsen, B. A., and Skjernaa, B. On the number of maximal bipartite subgraphs of a graph. J. Graph Theory 48 (2005), 127–132.
Cho, E.-K., Choi, I., and Park, B. On independent domination of regular graphs. J. Graph Theory, to appear, .
Fisk, S. A short proof of Chvátal’s watchman theorem. J. Combin. Theory Ser. B 24 (1978), 374.
Garey, M. R. and Johnson, M. R. Computers and Intractability. Freeman, New York, 1979.
Goddard, W. and Henning, M. A. Independent domination in graphs: A survey and recent results. Discrete Math. 313 (2013), 839–854.
Goddard, W. and Henning, M. A. Independent domination, colorings and the fractional idomatic number of a graph. Appl. Math. Comput. 382 (2020), 125340.
Goddard, W., Kuenzel, K. and Melville, E. Graphs in which all maximal bipartite subgraphs have the same order. Aequationes Math. 94 (2020), 1241–1255.
MacGillivray, G. and Seyffarth, K. Bounds for the independent domination number of graphs and planar graphs. J. Combin. Math. Combin. Comput. 49 (2004), 33–55.
Negami, S. and Nakamoto, A. Triangulations on closed surfaces covered by vertices of given degree. Graphs Combin. 17 (2001), 529–537.