functor

Definition from Wiktionary, a free dictionary

Contents 1 English 1.1 Noun 1.1.1 Translations 1.1.2 Derived terms

[edit] English

Wikipedia

[edit] Noun

functor (plural functors)

1. (Can we verify⁽⁺⁾ this sense?) A person who performs a function; a functionary or official
2. (grammar) a function word
3. (computing) a function object
4. (mathematics) a structure-preserving mapping between categories: if F is a functor from category C to category D, then F maps objects of C to objects of D and arrows of C to arrows of D such that any arrow f:X→Y of C is mapped to an arrow F(f): F(X) → F(Y) of D, such that if then , and such that identity arrows (and only identity arrows) are mapped to identity arrows. Note: the functor just described is covariant.

[edit] Translations

[edit] Derived terms

• contravariant functor
• representable functor