Topological information indices are graph invariants, based on information theory and calculated as - information content of specified equivalence relationships on the molecular graph. [Pg.195]

Graph theory is largely applied to the characterization of chemical structures, as well as to structure-property and structure-activity correlations, by means of so-called topological indices. These are numerical quantities based on various invariants or characteristics of molecular graphs. [Pg.23]

However, the assumptions needed to facilitate calculation and numerical approximation are themselves associated with an inherent error, although in most cases the direction, but not the magnitude, of the error is known. Moreover, within a series of related compounds the error term is usually considered to be approximately constant. All kinds of error are absent only for the most simple theoretical descriptors such as count descriptors or for descriptors directly derived from exact mathematical theories such as graph invariants. [Pg.305]

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