An edge-coloured path is monochromatic if all of its edges have the same colour. For a k-connected graph G, the monochromatic k-connection number of G, denoted by mck(G), is the maximum number of colours in an edge-colouring of G such that, any two vertices are connected by k internally vertex-disjoint monochromatic paths. In this paper, we shall study the parameter mck(G). We obtain bounds for mck(G), for general graphs G. We also compute mck(G) exactly when k is small, and G is a graph on n vertices, with a spanning k-connected subgraph having the minimum possible number of edges, namely [Formula presented]. We prove a similar result when G is a bipartite graph.
Qingqiong Cai is supported by National Key Research and Development Program of China (No. 2022YFA1006400 ), and Fundamental Research Funds for the Central Universities ( 050-63231193 ). Shinya Fujita is supported by JSPS KAKENHI (No. 23K03202 ). Henry Liu is partially supported by National Natural Science Foundation of China (No. 11931002 ), and National Key Research and Development Program of China (No. 2020YFA0712500 ). Boram Park is supported under the framework of an international cooperation program managed by the National Research Foundation of Korea ( NRF-2023K2A9A2A06059347 ).