\begin{figure}
  \centering
  \begin{tikzcd}[column sep=width("clipping at 0")]
    \gw
    \arrow[d, "\text{add node}"{sloped}, "\text{feature}"'{sloped} ]
    \arrow[r, "\text{change~} \Ncal \cap \Ecal", "\text{into~} \Ocal \cap \Ecal"' ]
    &
    \ogw
    \arrow[d, "\text{add node}"{sloped}, "\text{feature}"'{sloped}]
    \\
    [4ex]
    \fgw
    \arrow[r, "\text{change~} \Ncal \cap \Ecal", "\text{into~} \Ocal \cap \Ecal"']
    &
    \ofgw
  \end{tikzcd}
  \caption{Steps of constructing the graph discrepancies}
  \label{fig:transition}
\end{figure}
