Abstract
A simple relation between three-point correlation functions is derived for two-component materials. This relation enables one to find concise expressions for the Beran, Molyneux, and McCoy bounds on transport and elastic coefficients in terms of the volume fraction, f1, and two fundamental geometric parameters, ζ1 and η1. The parameter ζ1 also determines bounds on the complex electrical permittivity. No simple interpretation of ζ1 and η1 has been found.