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adjunction

/æˈdʒʌŋkʃən/

Meanings

noun

附加,添加。

Examples :

在现有公园里增添了新的游乐场,这使得它对家庭来说更具吸引力了。
noun

伴随, 伴随函子.

Given a pair of categories \mathcal{C} and \mathcal{D}: an anti-parallel pair of functors F:\mathcal{C}\rightarrow \mathcal{D} and G:\mathcal{D}\rightarrow \mathcal{C} and a natural transformation \eta:\mbox{id}C \rightarrow GF called “unit” such that for any object A \in \mathcal{C}, for any object B \in \mathcal{D}, and for any morphism f:A\rightarrow GB, there is a unique morphism g:FA\rightarrow B such that Gg \circ \etaA = f. (Note: there is another natural transformation called “counit” as well but its existence may be derived by theorem.) The pair of functors express a similarity between the pair of categories which is weaker than that of an equivalence of categories.

Examples :

教授用群论和线性代数的例子解释了两个数学结构之间的伴随关系(或伴随函子),展示了它如何在它们之间建立起一种形式上的联系。