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:
“In the Lord’s Prayer, the first petition is for daily bread. No one can worship God or love his neighbor on an empty stomach.”
—Woodrow Wilson (1856–1924)
“O, he’s drunk, Sir Toby, an hour agone; his eyes were set at eight i’ th’ morning.”
—William Shakespeare (1564–1616)