Padmakar-Ivan Index of Some Types of Perfect Graphs
Manju Sankaramalil Chithrabhanu, Kanagasabapathi Somasundaram · Discrete Mathematics Letters · 2022
The Padmakar-Ivan (PI) index of a graph G is defined aswhere NG(e) is the number of equidistant vertices for the edge e.A graph is perfect if for every induced subgraph H, the equation χ (H) = ω (H) holds, where χ (H) is the chromatic number and ω (H) is the size of a maximum clique of H.In this paper, the PI index of some types of perfect graphs is obtained.These types include co-bipartite graphs, line graphs, and prismatic graphs.