Editing Set theory (section)

=== Fuzzy set theory ===
{{Main|Fuzzy set theory}}

In set theory as Cantor defined and Zermelo and Fraenkel axiomatized, an object is either a member of a set or not. In ''[[fuzzy set theory]]'' this condition was relaxed by [[Lotfi A. Zadeh]] so an object has a ''degree of membership'' in a set, a number between 0 and 1. For example, the degree of membership of a person in the set of "tall people" is more flexible than a simple yes or no answer and can be a real number such as 0.75.