@Article{Awanis2022, author = "Awanis, Zata Yumni and Salman, A.N.M.", title = "The strong 3-rainbow index of some certain graphs and its amalgamation", journal = "Opuscula Math.", year = "2022", volume = "42", number = "4", pages = "527--547", doi = "https://doi.org/10.7494/OpMath.2022.42.4.527", url = "https://doi.org/10.7494/OpMath.2022.42.4.527", abstract = "We introduce a strong \(k\)-rainbow index of graphs as modification of well-known \(k\)-rainbow index of graphs. A tree in an edge-colored connected graph \(G\), where adjacent edge may be colored the same, is a rainbow tree if all of its edges have distinct colors. Let \(k\) be an integer with \(2\leq k\leq n\). The strong \(k\)-rainbow index of \(G\), denoted by \(srx_k(G)\), is the minimum number of colors needed in an edge-coloring of \(G\) so that every \(k\) vertices of \(G\) is connected by a rainbow tree with minimum size. We focus on \(k=3\). We determine the strong \(3\)-rainbow index of some certain graphs. We also provide a sharp upper bound for the strong \(3\)-rainbow index of amalgamation of graphs. Additionally, we determine the exact values of the strong \(3\)-rainbow index of amalgamation of some graphs.", keywords = "amalgamation, rainbow coloring, rainbow Steiner tree, strong \(k\)-rainbow index", issn = "1232-9274" }