$$ \Dg u & \rTo ^{e_1} & v & & \rTo \up{3pt} ^f \rTo \up{-3pt} _g & d \\ \uDashto >s & & \dTo >e & & & \uTo \\ w & \rTo ^{ee_1s} & w & {} = {\mit\Pi}k_i & \rTo & k_i \\ \endDg $$