In mathematics, the empty set is the set that has no things in it. For example, consider the set of integer numbers between two and three. Since there are no integer numbers between two and three, the set of integer numbers between them is empty.
Any statement about all elements of the empty set is considered true. For example, all integers between two and three are greater than seven. This only makes sense because there are no integers between two and three.
How to write it[change | change source]
There are two: