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:
“O I am miserable:
You cherished me, my mother,
But even you desert me.
I am sent to an empty place.”
—Hilda Doolittle (1886–1961)
“I move my thin legs into your office
and we work over the cadaver of my soul.
We make a stage set out of my past
and stuff painted puppets into it.”
—Anne Sexton (1928–1974)