Complete multipartite graphK2 K22,3 Turan graph T(n,r) T(n,r）=Kn1,n2,nr 1+2++,=nm:∈{L」[} K2,2,3 Complete multipartite graph Kn1,n2,...,nr Turán graph T(n, r) T(n, r) = Kn1,n2,...,nr n1 + n2 + ··· + nr = n ni ￾ ⇧￾n r ⇥ , ⇤n r ⌅⌃