OPERATIONS ON FUZZY SETS
We can introduce basic operations on fuzzy sets. Similar to the operations on crisp sets we also want to intersect, unify and negate fuzzy sets. In his very first paper about fuzzy sets [1], L. A. Zadeh suggested the minimum operator for the intersection and the maximum operator for the union of two fuzzy sets. It can be shown that these operators coincide with the crisp unification, and intersection if we only consider the membership degrees 0 and 1. For example, if A is a fuzzy interval between 5 and 8 and B be a fuzzy number about 4 as shown in the Figure below
In this case, the fuzzy set between 5 and 8 AND about 4 is
set between 5 and 8 OR about 4 is shown in the next figure the NEGATION of the fuzzy set A is shown below