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:
“The language of the younger generation ... has the brutality of the city and an assertion of threatening power at hand, not to come. It is military, theatrical, and at its most coherent probably a lasting repudiation of empty courtesy and bureaucratic euphemism.”
—Elizabeth Hardwick (b. 1916)
“They smote and fell, who set the bars
Against the progress of the stars,
And stayed the march of Motherland!”
—Will Henry Thompson (1848–1918)