A NOTE ON GENERALIZED RAINBOW CONNECTION OF CONNECTED GRAPHS AND THEIR NUMBER OF EDGES

2021 ◽  
Vol 66 (3) ◽  
pp. 3-7
Author(s):  
Anh Nguyen Thi Thuy ◽  
Duyen Le Thi

Let l ≥ 1, k ≥ 1 be two integers. Given an edge-coloured connected graph G. A path P in the graph G is called l-rainbow path if each subpath of length at most l + 1 is rainbow. The graph G is called (k, l)-rainbow connected if any two vertices in G are connected by at least k pairwise internally vertex-disjoint l-rainbow paths. The smallest number of colours needed in order to make G (k, l)-rainbow connected is called the (k, l)-rainbow connection number of G and denoted by rck,l(G). In this paper, we first focus to improve the upper bound of the (1, l)-rainbow connection number depending on the size of connected graphs. Using this result, we characterize all connected graphs having the large (1, 2)-rainbow connection number. Moreover, we also determine the (1, l)-rainbow connection number in a connected graph G containing a sequence of cut-edges.

2020 ◽  
Vol 3 (2) ◽  
pp. 95
Author(s):  
Alfi Maulani ◽  
Soya Pradini ◽  
Dian Setyorini ◽  
Kiki A. Sugeng

Let <em>G </em>= (<em>V</em>(<em>G</em>),<em>E</em>(<em>G</em>)) be a nontrivial connected graph. A rainbow path is a path which is each edge colored with different color. A rainbow coloring is a coloring which any two vertices should be joined by at least one rainbow path. For two different vertices, <em>u,v</em> in <em>G</em>, a geodesic path of <em>u-v</em> is the shortest rainbow path of <em>u-v</em>. A strong rainbow coloring is a coloring which any two vertices joined by at least one rainbow geodesic. A rainbow connection number of a graph, denoted by <em>rc</em>(<em>G</em>), is the smallest number of color required for graph <em>G</em> to be said as rainbow connected. The strong rainbow color number, denoted by <em>src</em>(<em>G</em>), is the least number of color which is needed to color every geodesic path in the graph <em>G</em> to be rainbow. In this paper, we will determine  the rainbow connection and strong rainbow connection for Corona Graph <em>Cm</em> o <em>Pn</em>, and <em>Cm</em> o <em>Cn</em>.


Author(s):  
Rizki Hafri Yandera ◽  
Yanne Irene ◽  
Wisnu Aribowo

AbstractLet  be a nontrivial connected graph, the rainbow-k-coloring of graph G is the mapping of c: E(G)-> {1,2,3,…,k} such that any two vertices from the graph can be connected by a rainbow path (the path with all edges of different colors). The least natural number


2013 ◽  
Vol 2 (2) ◽  
pp. 17
Author(s):  
Gema Hista Medika

Misalkan G adalah graf terhubung tak-trivial. Denisikan pewarnaan c :E(G) ! f1; 2; :::; kg, k 2 N, dimana dua sisi yang bertetangga boleh memiliki warnayang sama. Suatu u 􀀀 v path P di G dikatakan rainbow path jika tidak ada dua sisi diP yang memiliki warna sama. Graf G dikatakan rainbow connected jika setiap dua titikyang berbeda di G dihubungkan oleh rainbow path. Pewarnaan sisi yang menyebabkan Gbersifat rainbow connected dikatakan rainbow coloring. Rainbow connection number darigraf terhubung G, ditulis rc(G), didenisikan sebagai banyaknya warna minimal yangdiperlukan untuk membuat graf G bersifat rainbow connected. Misalkan c adalah rainbowcoloring dari graf terhubung G. Untuk dua titik u dan v di G, rainbow u-v geodesic padaG adalah rainbow u-v path yang panjangnya d(u; v), dimana d(u; v) adalah jarak antarau dan v (panjang u-v path terpendek di G). Graf G dikatakan strongly rainbow-connectedjika G memiliki suatu rainbow u-v geodesic untuk setiap dua titik u dan v di G. Mini-mum k yang terdapat pada pewarnaan c : E(G) ! f1; 2; :::; kg sedemikian sehingga Gadalah strongly rainbow-connected dikatakan strong rainbow connection number, src(G);di G. Jadi, rc(G) src(G) untuk setiap graf terhubung di G. Pada paper ini akan di-ulas kembali tentang strong rainbow connection number dari graf bipartit lengkap Ks;tdengan 1 s t dimana s; t 2 N adalah src(Ks;t) = d spte, sedangkan rainbow connec-tion number dari graf bipartit lengkap Ks;t dengan 2 s t dimana s; t 2 N adalahrc(Ks;t) = minfd spte; 4g.


2013 ◽  
Vol 2 (1) ◽  
pp. 78
Author(s):  
Sally Marhelina

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 aconnected graph G, denoted by rc(G) is the smallest number of colors needed such thatG is rainbow connected. In this paper, we will proved again that rc(G) ≤ 3(n + 1)/5 forall 3-connected graphs, and rc(G) ≤ 2n/3 for all 2-connected graphs.


2018 ◽  
Vol 10 (03) ◽  
pp. 1850039
Author(s):  
Yulong Wei ◽  
Min Xu ◽  
Kaishun Wang

In 2011, Li et al. [The (strong) rainbow connection numbers of Cayley graphs on Abelian groups, Comput. Math. Appl. 62(11) (2011) 4082–4088] obtained an upper bound of the strong rainbow connection number of an [Formula: see text]-dimensional undirected toroidal mesh. In this paper, this bound is improved. As a result, we give a negative answer to their problem.


2014 ◽  
Vol Vol. 16 no. 3 (Graph Theory) ◽  
Author(s):  
Xiaolong Huang ◽  
Hengzhe Li ◽  
Xueliang Li ◽  
Yuefang Sun

Graph Theory International audience The oriented diameter of a bridgeless graph G is min diam(H) | H is a strang orientation of G. A path in an edge-colored graph G, where adjacent edges may have the same color, is called rainbow if no two edges of the path are colored the same. The rainbow connection number rc(G) of G is the smallest integer number k for which there exists a k-edge-coloring of G such that every two distinct vertices of G are connected by a rainbow path. In this paper, we obtain upper bounds for the oriented diameter and the rainbow connection number of a graph in terms of rad(G) and η(G), where rad(G) is the radius of G and η(G) is the smallest integer number such that every edge of G is contained in a cycle of length at most η(G). We also obtain constant bounds of the oriented diameter and the rainbow connection number for a (bipartite) graph G in terms of the minimum degree of G.


2019 ◽  
Vol 7 (3) ◽  
pp. 43
Author(s):  
Fadillah Fadillah ◽  
Lyra Yulianti ◽  
Syafrizal Sy

Misalkan G = (V, E) adalah graf terhubung tak trivial. Definisikan pewarnaan c : E(G) → {1, 2, · · · , k} untuk suatu k ∈ N, dimana sisi yang bertetangga boleh diberi warna yang sama. Misalkan terdapat titik u dan v di G. Suatu lintasan-(u, v) di G dikatakan sebagai lintasan rainbow (rainbow path) jika semua sisi dalam lintasan-(u, v) tersebut memiliki warna yang berbeda. Graf G dikatakan bersifat rainbow connected terhadap pewarnaan c jika G memuat lintasan rainbow untuk setiap dua titik u dan v di G, sementara c dikatakan sebagai pewarnaan rainbow (rainbow coloring) dari G. Jika terdapat k warna yang digunakan dalam pewarnaan tersebut maka c dinamakan pewarnaan-k rainbow (rainbow k-coloring). Bilangan rainbow connection (rainbow connection number ) dari graf terhubung G, dinotasikan dengan rc(G), didefinisikan sebagai banyaknya warna minimum yang diperlukan untuk membuat graf G bersifat rainbow connected. Pada makalah ini akan ditentukan nilai bilangan rainbow connection dari graf yang merupakan hasil amalgamasi tiga graf lengkap, masing-masingnya dengan enam titik, 3K6, dengan graf roda W6, dinotasikan dengan graf (3K6 ∗ W6, v).Kata Kunci: Graf (3K6 ∗ W6, v), rainbow path, rainbow connection number


2017 ◽  
Vol 72 (4) ◽  
pp. 2079-2100 ◽  
Author(s):  
Wenjing Li ◽  
Xueliang Li ◽  
Colton Magnant ◽  
Jingshu Zhang

2013 ◽  
Vol 313 (19) ◽  
pp. 1884-1892 ◽  
Author(s):  
Jan Ekstein ◽  
Přemysl Holub ◽  
Tomáš Kaiser ◽  
Maria Koch ◽  
Stephan Matos Camacho ◽  
...  

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