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:
“Full bottles are quiet; it’s the empty ones that make all the noise.”
—Chinese proverb.
“She’s just a child,
but I’m the one who’s fainthearted.
She’s the woman,
but I’m the coward.
She bears that high, swollen set of breasts,
but I’m the one who’s burdened.
The heavy hips are hers,
but I’m unable to move.
It’s a wonder
how clumsy I’ve become
because of flaws
that shelter themselves
in another.”
—Amaru (c. seventh century A.D.)