\dvips \usepackage[nohug,fixed,labelstyle=\small,size=3em]{diagrams} % nohug: don't rotate labels on diagonal arrows % fixed: hack for \raise and \lower (see the manual, p.7) % labelstyle: smaller labels % size: bigger spacing \diagram{ & & \mathcal C^T \\ & \raise .5ex\hbox{$\ruTo^{F^T}$}\ \lower .5ex\hbox{$\ldTo_{U^T}$} & \uDashto_{K^T} \\ \mathcal C & \pile{\rTo^F\\\lTo_U} & \mathcal D \\ & \lower .5ex\hbox{$\luTo_{U_T}$}\ \raise .5ex\hbox{$\rdTo^{F_T}$} & \uDashto_{K_T} \\ & & \mathcal C_T }