**Topological Indices Derived From Parts of a Universal Matrix**

**Anton Perdih*, Franc Perdih**

*Department of Chemistry
and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000
Ljubljana, Slovenia.
E-mail: Anton.Perdih@email.si*

Absrtract

Using the approach of mutual contribution of vertices to the value
of topological indices derived from parts of a universal matrix gave the idea
how to develop new topological indices. Some of the newly developed indices are
useful indices of Octane Numbers and of Critical Pressure of alkanes of equal
carbon number, giving rise to abs(R_{fit}) > 0.99. Using them we
estimated the missing data of Octane Numbers of 2,3-dimethyl butane and 2,2,3,3-tetramethyl
butane, as well as of nonanes and decanes. The best analogous indices derived
from the reverse variants of this universal matrix are in general less useful.
Some types of newly developed indices are also useful for structural
interpretation of several known indices.