# presheaf

Noun

(*plural* presheaves)

- (category theory) A contravariant functor whose domain is a category whose objects are open sets of a topological space and whose morphisms are inclusion mappings.
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Usage notes

- If the topological space being referred to is denoted as
*X*and the presheaf's codomain as*A*, then the presheaf is said to be "on*X*, with values in*A*".

Origin

*pre-* + *sheaf*