Kragujevac J. Math. 25 (2003) 51-54.

GRAPHS WITH SMALLEST SUM OF SQUARES OF VERTEX DEGREES

Ivan Gutman

Faculty of Science, P. O. Box 60, 34000 Kragujevac, Serbia and Montenegro

(Received September 2, 2003)

Abstract. Graphs with n vertices, m edges, and with smallest sum of squares of the vertex degrees are characterized. These are the graphs in which the degree of any vertex is equal to either [2m/n] or [2m/n]. Such graphs exist for all n £ 1 and 0 £ m £ n(n-1)/2.