The notion of a mass assignment corresponding to a discrete fuzzy set
is generalised to include all fuzzy sets. The definition is motivated
by considering a possible mechanism by which an intelligent agent coul
d extend set theoretic operations to fuzzy sets. This same mechanism a
lso suggests an alternative definition for the conditional probability
of fuzzy sets. It is noted that this definition is probability/possib
ility consistent and it is shown that in the case, where the probabili
ty distribution on the domain has a density function then the conditio
nal probability of f given g can be expressed as the probability of f
calculated relative to a conditional density function dependent on g.
This result is used to develop an analytical method for calculating co
nditional probabilities of fuzzy subsets of the reals, where the membe
rship functions of f and g and the density function are continuous pie
cewise linear functions. Such a method has applications to the develop
ment of a general semantic unification in Fril. (C) 1998 Elsevier Scie
nce B.V. All rights reserved.