5.1.39. (!) Prove that every k-chromatic graph has at least ([k],[2]) edges. Use this to prove
that if G is the union of m complete graphs of order m, then chi (G)<=1+msqrt(m-1).
Can you explain proof with sketching a graph with the proof.
5.1.39. Prove that every k-chromatic graph has at least () edges. Use this to prove that if G is the union of m complete graphs of order m, then x(G) 1 + m/m - 1
Can you explain proof with sketching a graph with the proof.