A set is a collection of individual elements in the domain . The universal set contains every element in . The null set contains no element.

•	If is a set in the domain , must be a subset of the universal set , denoted as .
•	If consists of some but not all elements, is then called a proper subset of , denoted as .

The definition of union ("or"), intersection ("and"), and complement ("not") can be illustrated by Venn Diagrams as follows:

Suppose that and are two sets in the same domain whose universal set is .

•	The union of and consists of all elements which belong to either or , denoted by .
•	The intersection of and consists of only elements which belong to both and , denoted by .
•	The complement of consists of elements which do not belong to , denoted by .

Distributive Laws

De Morgan's Laws