交换图中的方程标签

Question

我想要一个交换图

\begin{equation*} 
\begin{tikzcd}[row sep=huge]     

    A \, \arrow[r] \arrow[d] & B  \arrow[d] \\ 

    C & D \arrow[l] \\

\end{tikzcd} 
\end{equation*}

在交换图中，我希望用如下方程代替符号“A”

\begin{equation} \label{myequation} 
\begin{array}{rcl} 

E & = & m c^2 \\

E & = & m c^3 

\end{array} 
\end{equation}

并且我想用 引用外部的那个方程\ref{myequation}。我该怎么做？

Answer 1

仍然不确定我是否理解了你的问题，但我想这可能是你想要的。

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}
\begin{document}
\begin{equation} 
\begin{tikzcd}[row sep=huge,ampersand replacement=\&]     
    \label{eq:Schmarrn}(\theequation)~\left\{\begin{array}{@{}r@{\,}c@{\,}l} 
E & = & m c^2 \\
E & = & m c^3 
\end{array}\right.  \, \arrow[r] \arrow[d] \& B  \arrow[d] \\ 
    C \& D \arrow[l] \\
\end{tikzcd} \notag\stepcounter{equation}
\end{equation}
Einstein said that 
\begin{equation}\label{eq:Einstein}
E  =  m c^2
\end{equation}
and the second equality in \eqref{eq:Schmarrn} is not quite right. On the other
hand, \eqref{eq:Einstein} is correct.
\end{document}

至于你的请求。基于这个答案你可以这样做：

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}
\begin{document}
\begin{align}\label{eq:Schmarrn}
\makebox[\displaywidth]{
\begin{tikzcd}[row sep=huge,ampersand replacement=\&]     
A  \, \arrow[r] \arrow[d] \& 
    \left.\begin{array}{@{}r@{\,}l} 
E & =  m c^2 \\
E & =  m c^3 
\end{array}\right\}  \arrow[d] \\ 
    C \& D \arrow[l] \\
\end{tikzcd}} \raisetag{24.4ex}
\end{align}
Einstein said that 
\begin{equation}\label{eq:Einstein}
E  =  m c^2
\end{equation}
and the second equality in \eqref{eq:Schmarrn} is not quite right. On the other
hand, \eqref{eq:Einstein} is correct.
\end{document}

Answer 2

我想你想要这样的东西：

这来自于将你想要的文本“带有标签的方程式 1”括在 中\text{...}。否则 LaTeX 会认为带标签的方程式1作为一个单一变量——它需要\,作为单词分隔符。

\documentclass{article}
\usepackage{amsmath,amssymb,tikz-cd}

\begin{document}
    \begin{equation*}
    \begin{tikzcd}[row sep=huge]
    \text{equation 1 with a label } \arrow[r] \arrow[d] &   
    \text{equation 2 with a label } \arrow[d] \\
                                A                       & 
                                B   \arrow[l] \\
    \end{tikzcd}
    \end{equation*}
\end{document}

\end{document}