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

### Other articles related to "set, empty set, sets, empty":

... order, and the dataflow confluence operator is

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... Note that this definition also includes as faces the

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... A

**set**is pure if all of its members are

**sets**, all members of its members are

**sets**, and so on ... For example, the

**set**containing only the

**empty set**is a nonempty pure

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**sets**only ...

**Empty Set**- Questioned Existence - Philosophical Issues

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**empty set**is not the same thing as nothing rather, it is a

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

“The monotonous dead clog me up and there is only

black done in black that oozes from the strongbox.

I must disembowel it and then *set* the heart, the legs,

of two who were one upon a large woodpile

and ignite, as I was once ignited, and let it whirl

into flame....”

—Anne Sexton (1928–1974)

“I consider that a man’s brain originally is like a little *empty* attic, and you have to stock it with such furniture as you choose.”

—Sir Arthur Conan Doyle (1859–1930)