Let G = (V (G),E(G)) be a nontrivial connected graph of order n with an edge-coloring c : E(G) → {1, 2, . . . , q}, q ∈ N, where adjacent edges may be colored the same. A tree T in G is a rainbow tree if no two edges of T receive the same color. For a vertex set S ⊆ V (G), a tree connecting S in G is called an S-tree. The minimum number of colors that are needed in an edge-coloring of G such that there is a rainbow S-tree for each k-subset S of V (G) is called the k-rainbow index of G, denoted by rxk(G), where k is an integer such that 2 ≤ k ≤ n. Chartrand et al. got that the k-rainbow index of a tree is n−1 and the k-rainbow index of a unicyclic graph is n−1 or n−2. So there is an intriguing problem: Characterize graphs with the k-rainbow index n − 1 and n − 2. In this paper, we focus on k = 3, and characterize the graphs whose 3-rainbow index is n − 1 and n − 2, respectively.
@article{bwmeta1.element.doi-10_7151_dmgt_1783, author = {Xueliang Li and Ingo Schiermeyer and Kang Yang and Yan Zhao}, title = {Graphs with 3-Rainbow Index n - 1 and n - 2}, journal = {Discussiones Mathematicae Graph Theory}, volume = {35}, year = {2015}, pages = {105-120}, zbl = {1307.05051}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_7151_dmgt_1783} }
Xueliang Li; Ingo Schiermeyer; Kang Yang; Yan Zhao. Graphs with 3-Rainbow Index n − 1 and n − 2. Discussiones Mathematicae Graph Theory, Tome 35 (2015) pp. 105-120. http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_7151_dmgt_1783/
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