\begin{figure}[ht]

  \begin{tabular}{cc}
  \begin{minipage}[b]{0.4\hsize}
  \centering
  
  \begin{equation*}
    \begin{aligned}
    &\tau_p  &::=   &\;R              &[real]& \\
    &        &\;  | &\;N              &[nat] & \\
    &\tau    &::=   &\;\tau_p         &      & \\
    &        &\;  | &\;\tau \to \tau  &[fun]&
            % |&\quad \langle \tau \rangle
    \end{aligned}
  \end{equation*}
  \textrm{Types}
  \end{minipage}&
  
  \begin{minipage}[b]{0.4\hsize}
    \centering
    \begin{equation*}
      \begin{aligned}
          &v_p  &::=&\; r \;   r \in \mathbb{R}&\\
          &     &\;|&\; n \;   n \in \mathbb{N}&\\
          &v    &::=&\; v_p                    &\\
          &     &\;|&\; cls(\lambda x.e, E)    &
                %%|& \quad (e_1,e_2) \quad & [product]\\
                %%|& \quad \pi_n e \quad n\in \mathbb{N},\; n>0 \quad & [project]\\
                %%|& \quad \langle e \rangle \quad & [code] \\
                %%|& \quad \textasciitilde e \quad & [escape]
      \end{aligned}
    \end{equation*}
    \textrm{Values}
    \end{minipage}\\
    \multicolumn{2}{l}{
  \begin{minipage}[t]{0.4\hsize}
    \begin{equation*}
      \begin{aligned}
&e&::=& \; x                         \;\;  (x \in {v_p})     & [value]    &\\
& &  |& \; \lambda x.e                                     & [lambda]   &\\
& &  |& \; e_1 \; e_2                                      & [app]      &\\
& &  |& \; let\; x = e_1\; in\; e_2                        & [let]      &\\
& &  |& \; if\; (e_c)\; e_t\; else\; e_e                   & [if]       &\\ 
& &  |& \; delay\; n \; e_1 \; e_2   \;\;  (n \in \mathbb{N})& [delay]    &\\
& &  |& \; feed \; x.e                                     & [feed]     &\\
& &  |& ...                                                &            &
                %%|& \quad (e_1,e_2) \quad & [product]\\
                %%|& \quad \pi_n e \quad n\in \mathbb{N},\; n>0 \quad & [project]\\
                %%|& \quad \langle e \rangle \quad & [code] \\
                %%|& \quad \textasciitilde e \quad & [escape]
      \end{aligned}
    \end{equation*}
  \end{minipage}
  }
\end{tabular}
\centering \textrm{Terms} %置き方おかしいけどこれで上手くレイアウトされてるのでこのまま
\caption{\label{fig:syntax_v}{\it$\lambda_{mmm}$の値、型、項の定義の抜粋。基本演算などは省略した。}}
\end{figure}