Definitions

DISJOINT SETSOpen article

Disjoint sets are sets that have no common elements.

EMPTY SETOpen article

The empty set is a set that contains no elements.

PROPER SUBSETOpen article

A proper subset is a subset that is not equal to the original set and therefore contains fewer elements.

SETOpen article

A set in mathematics is a collection of unique elements, which may be numbers, symbols, or other objects.

SET DIFFERENCEOpen article

The difference of sets A and B is the set of elements that belong to A but do not belong to B.

SET EQUALITYOpen article

Two sets are equal if they contain exactly the same elements.

SET INTERSECTIONOpen article

The intersection of sets is the set that contains only the elements that belong to both sets.

SET UNIONOpen article

The union of sets is the set that contains all elements from both sets.

SUBSETOpen article

A subset is a set whose every element also belongs to another set.