Another extremal problem for Turan graphs
Let K(G) and \(\omega\) (G) be the clique graph and clique number of a graph G. For \(1<r<n\), let \(F(n,r)=\max_{G}\{| K(G)|:| V(G)| =n\) and \(\omega (G)=r\}\). A Turan graph \(T(n,r)\) is a multipartite graph with vertices \(v_ 1,v_ 2,...,v_ n\), and \(v_ iv_ j\in E(G)\) if and only if \(i\neq j\) (mod r). Theorem: Let G be a graph of order n with \(\omega (G)=r<n\). Then \(| K(G)| =F(n,r)\) if and only if \(G\sim T(n,r)\).
scientific article; zbMATH DE number 4023322