FUNCTOR

Etymology

Noun

functor (plural functors)

(grammar) A function word.

(object-oriented programming) A function object.

(category theory) A category homomorphism; a morphism from a source category to a target category which maps objects to objects and arrows to arrows, in such a way as to preserve domains and codomains (of the arrows) as well as composition and identities.

Hyponym: endofunctor

In the category of categories, \(\mathbb{CAT}\), the objects are categories and the morphisms are functors.

\(\overline{F} : \overrightarrow{X} \rightarrow \overline{F(\overrightarrow{X})}, F^0 : \overrightarrow{X}\rightarrow F(\overrightarrow{X})^0, F^c : \overrightarrow{X} \rightarrow F(\overrightarrow{X})^c\).

\(S(M,X) = \bigoplus^\infty_{r=0} \left ( M(r)\otimes X^{\otimes r}\right )_{\Sigma_r}\).

Source: Wiktionary



RESET



Word of the Day

22 November 2024

SHEET

(noun) (nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind


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Coffee Trivia

Some 16th-century Italian clergymen tried to ban coffee because they believed it to be “satanic.” However, Pope Clement VII loved coffee so much that he lifted the ban and had coffee baptized in 1600.

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