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Cardinality of a Set

The cardinality of a set refers to the number of elements in the set. For a finite set A, the cardinality of
A, denoted by |A|, is simply the count of its elements.

For example, if A = {1, 2, 3, 4}, then |A| = 4. Cardinality is a fundamental concept in set theory and plays a
crucial role in comparing set sizes, especially when dealing with infinite sets.

Element Count Finite Sets Infinite Sets

Number of unique items in a set Cardinality concepts extend to infinite sets

Cardinality is a specific number