A view of surface contact as the parallel interactions between surfaces doe
s not conform to the customary random processes models inherited from commu
nications theory. One aspect of the interactions is the effect of local def
ormations on neighbouring parts of the surfaces. These correlations are dis
tinguished as geometrical and physical. The geometrical interaction is cons
idered in this paper, resulting in a discrimination between degrees of peak
s interaction. (C) 1999 Elsevier Science B.V. All rights reserved.