(1, 2)-rainbow connection number at most 3 in connected dense graphs

Main Authors: Doan, Trung Duy; School of Applied Mathematics and Informatics, Hanoi University of Science and Technology, Hanoi, Vietnam, Duyen, Le Thi; School of Applied Mathematics and Informatics, Hanoi University of Science and Technology, Hanoi, Vietnam
Format: Article info application/pdf eJournal
Bahasa: eng
Terbitan: GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB , 2023
Subjects:
(1
Online Access: https://www.ejgta.org/index.php/ejgta/article/view/1221
https://www.ejgta.org/index.php/ejgta/article/view/1221/pdf_275
Daftar Isi:
  • Let G be 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 consider the (1, 2)-rainbow connection number at most 3 in some connected dense graphs. Our main results are as follows: (1) Let n ≥ 7 be an integer and G be a connected graph of order n. If ω(G)≥n − 3, then rc1, 2(G)≤3. Moreover, the bound of the clique number is sharpness. (2) Let n ≥ 7 be an integer and G be a connected graph of order n. If |E(G)| ≥ C(n − 3, 2)+7, then rc1, 2(G)≤3.