e≤(n-0)(n-O+1) 令LetG1,G2,…, Gobe o components of G.G;has vertices for i==1,2,…,o,andn1+n2+…+non and e;<-n,(n (n-O)(n-)+1), 2 The complete graph on n-O+l vertices and o-1 isolated vertices( )( 1) 2 1 2. e  n − n − + ❖ Let G1 ,G2 ,…,Gωbe ω components of G. Gi has ni vertices for i=1,2,…, ω, and n1+n2+…+nω=n ，and ( 1) 2 1 ei  ni ni − ( )( 1) 2 1 n − n − + ， The complete graph on n-ω+1 vertices and ω-1 isolated vertices