A finite set is a set admitting a bijection with for some nonnegative integer , including the empty set at . The number is uniquely determined and is its cardinality.
Every injective map from a finite set to itself is surjective, and conversely. This follows by counting image elements: an injection cannot omit an element without reducing the size of its image. For infinite sets the property can fail, as is an injection of the natural numbers into themselves that omits zero. The bijection definition gives a precise meaning to finite without reusing the word in its own definition.
The property of being a finite set. In a finite set, an injective self-map is surjective; this implication can fail for an infinite set.

Ancestors (6)

  1. Set
  2. Set theory
  3. Foundations of mathematics
  4. Area of mathematics
  5. Mathematics
  6. Home

Discussion (0) New discussion

There are no discussions about this article yet.

Articles by others on the same topic (1)

A finite set is a collection of distinct elements that has a limited or countable number of members. In mathematical terms, a set \( S \) is defined as finite if there exists a natural number \( n \) such that the set contains exactly \( n \) elements. For example, the set \( S = \{1, 2, 3\} \) is a finite set because it contains three elements.