User:AxelBoldt/test

So:



\begin{array}{ccc} \operatorname{Hom}_C(FY',X)&\xrightarrow{\Phi_{Y',X}}&\operatorname{Hom}_D(Y',GX)\\ \\ \downarrow{\scriptstyle \operatorname{Hom}_C(Fg,f)}&&\downarrow{\scriptstyle \operatorname{Hom}_D(g,Gf)}\\ \\ \operatorname{Hom}_C(FY,X')&\xrightarrow{\Phi_{Y,X'}}&\operatorname{Hom}_D(Y,GX')\\ \end{array} $$