Yoneda lemma

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Yoneda lemma

  • The Yoneda embedding: the functional functor: \begin{align*} Y: \mathsf{C} \to {\mathsf{Fun}}(\mathsf{C}, {\mathsf{Set}}) = \underset{ \mathsf{pre} } {\mathsf{Sh} }(\mathsf{C}, {\mathsf{Set}}) \quad Y({-}) := {\mathsf{Fun}}({-}, {\mathsf{Set}}) \circ { {({-})}^{\operatorname{op}}} \quad X \mapsto \mathop{\mathrm{Hom}}_{\mathsf{C} } ({-}, X) \end{align*} attachments/Pasted%20image%2020210511151053.png

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