An edge-colored graph G is rainbow connected, if any two vertices are connected by a path whose edges have distinct colors. The rainbow connection number of a connected graph G, denoted rc(G), is the smallest number of colors that are needed in order to make G rainbow connected. In this paper we show that rc(G) ≤ 3 if |E(G)| ≥ [...] + 2, and rc(G) ≤ 4 if |E(G)| ≥ [...] + 3. These bounds are sharp.
@article{bwmeta1.element.doi-10_7151_dmgt_1692, author = {Xueliang Li and Mengmeng Liu and Ingo Schiermeyer}, title = {Rainbow Connection Number of Dense Graphs}, journal = {Discussiones Mathematicae Graph Theory}, volume = {33}, year = {2013}, pages = {603-611}, zbl = {1275.05022}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_7151_dmgt_1692} }
Xueliang Li; Mengmeng Liu; Ingo Schiermeyer. Rainbow Connection Number of Dense Graphs. Discussiones Mathematicae Graph Theory, Tome 33 (2013) pp. 603-611. http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_7151_dmgt_1692/
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