
4.4 Review
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due to the way a complement is constructed in fuzzy logic using the
negation operator (see Table 4.1). A complement measures the degree of
distance between complete membership (having a truth value of [1]) and
the complement set’s corresponding membership.
Therefore, when A[x] has a membership of μ[.8], the complement,
∼A[x], has a membership of μ[.2]. We interpret this to mean that x is
strongly a member of fuzzy set A and weakly a member of fuzzy set ∼A.
In such a case we are — in violation of Aristotle’s law and the prevailing
law of bivalence in Boolean logic — affirming that x is a member of both
sets. We can easily see this in Figure ...