## bgcse core

**sets**

A
set is a collection of items, usually of the same kind. Each item in a set is called an element or member. In a finite set it is possible to count and name all the elements in the set. In an infinite set it is impossible to count or name all the elements in the set. Two sets are equal if they both have the same elements. Two sets are equivalent if they both have the same number of elements. Disjoint sets have no intersection. |
## union & intersection |