Functor
IN CATEGORY THEORY, A MAPPING BETWEEN CATEGORIES THAT PRESERVES THEIR STRUCTURE (IDENTITY MORPHISMS, COMPOSITION OF MORPHISMS)
Covariant functor; Contravariant functor; Cofunctor; Functorial; Functors; Functoriality; Endofunctor; Bifunctor; Covariance and contravariance of functors; Identity functor; Multifunctor; Functor (category theory); Covariance (categories); Opposite functor; Constant functor; Selection functor; Category homomorphism; Dual functor; Covariance and contravariance (category theory)
In mathematics, specifically category theory, a functor is a [between categories]. Functors were first considered in [[algebraic topology, where algebraic objects (such as the fundamental group) are associated to topological spaces, and maps between these algebraic objects are associated to continuous maps between spaces.