Many people with fibromyalgia continue to work full or part time. But the chronic pain and fatigue associated with fibromyalgia often make working very difficult. If you are employed, it's important to learn about managing fibromyalgia symptoms and coping with pain and fatigue.
Definition of SET THEORY. : a branch of mathematics or of symbolic logic that deals with the nature and relations of sets.
Answer Wiki. Standard Zermelo-Fraenkel (ZF) set theory defines zero as being the empty set, or in mathematical notation 0 = {}. Though it can also be defined as the set that only contains the empty set, but that's somewhat pointless for this situation (I just thought I'd mention it in case someone else uses this definition instead).