Yoneda embedding (source code)

= Yoneda embedding
{c}
{title2=$y:\mathcal C\to[\mathcal C^{\mathrm{op}},\mathbf{Set}]$}
{wiki}

The Yoneda embedding sends $A$ to $\mathcal C(-,A)$. The <Yoneda lemma> identifies natural transformations $yA\to yB$ with morphisms $A\to B$, so the embedding is <full and faithful>. It preserves every limit that exists in $\mathcal C$.