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empty set

Set (in mathematics) containing no elements

Also known as null set

Instance of: set
, open set
, closed set
+3 more
Part of: list of types of sets

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

In mathematics, the empty set or void set is the unique set having no elements; its size or cardinality is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set, while in other theories, its existence can be deduced. Many possible properties of sets are vacuously true for the empty set.

Overview

All data

30 statements · 7% with external sources · numbers in brackets are citations

Set cardinality: zero
Different from: y
singleton of 0
null set
TeX string: \empty
\emptyset
\varnothing
Opposite of: non-empty set
Notation: ∅
Said to be the same as: 0-ad

On other databases

13 identifiers linking empty set across the web's reference databases

Data quality

statements

externally sourced

Source last edited September 27, 2026. AIDb refreshes this page daily.

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AIDb. (2026). empty set (Q226183). Retrieved from https://aidb.si/e/empty-set-Q226183