Subset

A set X is a subset of a set Y if all elements of X are also in Y.

Examples:

• The set {1, 2} is a subset of {1, 2, 3}.
• The set {1, 2} is also a subset of itself.
• The set of natural numbers is subset of the rational numbers.
• The set {x : x is a prime number greater than 2000} is a subset of {x : x is an odd number greater than 1000}

See also:

• Proper subset