DESCRIPTION OF CYCLIC AND BRANCHED-ACYCLIC HYDROCARBONS BY VARIANTS OF THE HYPER-WIENER INDEX

The hyper-Wiener index R was originally defined for acyclic structures . Four different techniques have been proposed so far in order to exte nd this definition for cycle-containing structures. A computational me thod for the ''delete path'' version of R is presented for molecules c ontaining a single cycle and a side branch. Formulas for simple cycles are derived for the ''delete path'' and for the ''count path'' versio ns of R. The variants of the hyper-Wiener number are compared with res pect to their use in quantitative structure-property relationships.