A function between categories which maps objects to objects and morphisms to morphisms. Functors exist in both covariant and contravariant types.

See also

Category, Contravariant Functor, Covariant Functor, Eilenberg-Steenrod Axioms, Forgetful Functor, Morphism, Schur Functor, Tensor Product Functor

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Cite this as:

Weisstein, Eric W. "Functor." From MathWorld--A Wolfram Web Resource.

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