# Empty Set

In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality (count of elements in a set) is zero. Some axiomatic set theories assure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced. Many possible properties of sets are trivially true for the empty set.

Null set was once a common synonym for "empty set", but is now a technical term in measure theory.

Read more about Empty Set:  Notation, Properties

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### Famous quotes containing the words set and/or empty:

You have a row of dominoes set up; you knock over the first one, and what will happen to the last one is that it will go over very quickly.
Dwight D. Eisenhower (1890–1969)

January, month of empty pockets!... Let us endure this evil month, anxious as a theatrical producer’s forehead.
Colette [Sidonie Gabrielle Colette] (1873–1954)