On the Szeged Index of monocyclic graphs

Szeged index (S-z) is a new topological index based on distances between ve rtices of a graph. It is the extension of Wiener index (W) on cyclic graphs . These indices of cyclic molecules differ, in the general case, S-z exceed s W. Otherwise, the relation between S-z and W of cyclic molecules is not y et established thoroughly. In order to get some information about this rela tions, we have examined monocyclic molecules consisting n vertices (n = eve n, > or = 4) and observed that S-z = 2 W.