Boolean
Representation
of Fuzzy Sets
35
Boolean Representation of
Fuzzy Sets
Costas Drossos and George Markakis zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP
University of Patras, Greece
Introduction
General representation theorems for L-fuzzy quantities was given by Höhle[1],
using lattice theoretic concepts, which include the Negoita-Ralescu set
representation as a special case (see also[2, pp. 95-6] for related works).
In this article we would like to follow a different path, restricting the generality
and gaining in structure and understanding of the nature of fuzzy sets.
Before we proceed, it is necessary to clear up the concept of a Boolean-
valued Dedekind cut, which is of interest in its own right.
Boolean-valued Dedekind Cuts
Ordinary Dedekind cuts in may be identified either with the upper or with
the lower open array. In this way a Dedekind cut in is a value of one of the
following functions:
where
or,
where,
By definition,
(i) u(q) ↓ as q ↑ andζψξωϖυτσρθπονμλκϕιηγφεδχβαΖΨΞΩςΥΤΣΡΘΠΟΝΜΛΚϑΙΗΓΦΕ∆ΧΒΑ È
q Î
u(q) = Ç
qζψξωϖυτσρθπονμλκϕιηγφεδχβαΖΨΞΩςΥΤΣΡΘΠΟΝΜΛΚϑΙΗΓ Î
u(q) = .
(ii) u is o-continuous from the right, i.e.
and l is o-continuous from the left, i.e.
Kybernetes, Vol. 22 No. 3, 1993,
pp. 35-40, © MCB University
Press, 0368-492X