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
Famous quotes containing the words empty and/or set:
“An empty book is like an infants soul, in which anything may be written. It is capable of all things, but containeth nothing. I have a mind to fill this with profitable wonders.”
—Thomas Traherne (16361674)
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—Lewis Carroll [Charles Lutwidge Dodgson] (18321898)