Cardinality

The size of a set, denoted $|A|$. For a finite set, the cardinality is the number of elements it contains.

Context

Cardinality is used throughout discrete math and computer science. For example, the set $A=\{1,2,3\}$ has cardinality $|A|=3$. The concept extends to infinite sets, where sets can be countably infinite (like the integers) or uncountably infinite (like the real numbers).

See Also

• set
• subset
• power set
• Empty Set
• complement