SET Theory - Definition, Key Concepts 

Set theory is a branch of mathematical logic that deals with the study of sets, which are collections of distinct objects. It provides a formal foundation for mathematics by defining basic concepts such as sets, elements, subsets, and operations on sets.

In set theory, a set is considered as an unordered collection of objects, known as elements or members, which can be anything from numbers to other sets. The elements of a set are unique, meaning that duplicates are not allowed within a set.

Key concepts in set theory include:

1. Elements: Objects that belong to a set.
2. Sets: Collections of distinct elements.
3. Subsets: Sets that contain only elements that are also contained in another set.
4. Union: The operation that combines two sets to form a new set containing all the elements from both sets.
5. Intersection: The operation that creates a new set containing only the elements that are common to two or more sets.
6. Complement: The set of elements that do not belong to a particular set.
7. Power set: The set of all possible subsets of a given set, including the empty set and the set itself.