Английская Википедия:Essentially surjective functor

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In mathematics, specifically in category theory, a functor

<math>F:C\to D</math>

is essentially surjective if each object <math>d</math> of <math>D</math> is isomorphic to an object of the form <math>Fc</math> for some object <math>c</math> of <math>C</math>.

Any functor that is part of an equivalence of categories is essentially surjective. As a partial converse, any full and faithful functor that is essentially surjective is part of an equivalence of categories.[1]

Notes

  1. Mac Lane (1998), Theorem IV.4.1

References

External links

Шаблон:Categorytheory-stub Шаблон:Functors