如何移动态射的描述

Question

我想画一个交换图，我完成了，

\[
    \begin{tikzcd}[row sep=2em, column sep = 2em]
   0\arrow[rr]&&
   D' \arrow[rr,"\sigma_1"] \arrow[dr,dashed, swap,"d'"] \arrow[dd,swap] &&
    D \arrow[dd] \arrow[dr,dashed,swap,"d"] \arrow[rr,"\sigma_2"]&&
    D'' \arrow[rr]\arrow[dr,dashed ,swap,"d'' "]\arrow[dd] &&0\\
    &0\arrow[rr] && C' \arrow[rr,"\gamma_1"] \arrow[dd]&&
    C \arrow[dd]\arrow[rr,"\gamma_2"]&&
    C''\arrow[dd]\arrow[rr] &&
    0\\
   0\arrow[rr] &&
   B \arrow[rr,"\beta_1"] \arrow[dr,dashed,swap,"\partial' "] && B \arrow[dr,dashed,swap,"\partial "]\arrow[rr,"\beta_2"]&& B''\arrow[dr,dashed,swap,"\partial'' "]\arrow[rr]&&0 \\
    &0\arrow[rr]&& A' \arrow[rr,"\alpha_1"]&& A\arrow[rr,"\alpha_2"]&& A''\arrow[rr]&& 0
    \end{tikzcd}
\]

但是我有一个小问题，地图 beta 和 gamma 的描述与向下的地图重合。如何将它稍微移动一点，这样它就不会被向下的线切断？

Answer 1

将选项near start、near end、very near start之一添加very near end到 的选项中\arrow。如需更精细的控制，请使用pos=n相反，n是 0 至 1 之间的数字。

\documentclass{article}
\usepackage{tikz-cd}
\begin{document}

\[
    \begin{tikzcd}[row sep=2em, column sep = 2em]
   0\arrow[rr]&&
   D' \arrow[rr,"\sigma_1"] \arrow[dr,dashed, swap,"d'"] \arrow[dd,swap] &&
    D \arrow[dd] \arrow[dr,dashed,swap,"d"] \arrow[rr,"\sigma_2"]&&
    D'' \arrow[rr]\arrow[dr,dashed ,swap,"d'' "]\arrow[dd] &&0\\
    &0\arrow[rr] && C' \arrow[rr,"\gamma_1",near start] \arrow[dd]&&
    C \arrow[dd]\arrow[rr,"\gamma_2",near start]&&
    C''\arrow[dd]\arrow[rr] &&
    0\\
   0\arrow[rr] &&
   B \arrow[rr,"\beta_1",near start] \arrow[dr,dashed,swap,"\partial' "] && B \arrow[dr,dashed,swap,"\partial "]\arrow[rr,"\beta_2",very near start]&& B''\arrow[dr,dashed,swap,"\partial'' "]\arrow[rr]&&0 \\
    &0\arrow[rr]&& A' \arrow[rr,"\alpha_1"]&& A\arrow[rr,"\alpha_2"]&& A''\arrow[rr]&& 0
    \end{tikzcd}
\]

\end{document}

Answer 2

只需向每个相关标签添加一个四边形：

\documentclass{article}
\usepackage{tikz-cd}

\begin{document}

\[
    \begin{tikzcd}[row sep=2em, column sep = 2em]
   0\arrow[rr]&&
   D' \arrow[rr,"\sigma_1"] \arrow[dr,dashed, swap,"d'"] \arrow[dd,swap] &&
    D \arrow[dd] \arrow[dr,dashed,swap,"d"] \arrow[rr,"\sigma_2"]&&
    D'' \arrow[rr]\arrow[dr,dashed ,swap,"d'' "]\arrow[dd] &&0\\
    &0\arrow[rr] && C' \arrow[rr,"\gamma_1\quad"] \arrow[dd]&&
    C \arrow[dd]\arrow[rr,"\gamma_2\quad"]&&
    C''\arrow[dd]\arrow[rr] &&
    0\\
   0\arrow[rr] &&
   B \arrow[rr,"\beta_1\quad"] \arrow[dr,dashed,swap,"\partial' "] && B \arrow[dr,dashed,swap,"\partial "]\arrow[rr,"\beta_2\quad"]&& B''\arrow[dr,dashed,swap,"\partial'' "]\arrow[rr]&&0 \\
    &0\arrow[rr]&& A' \arrow[rr,"\alpha_1"]&& A\arrow[rr,"\alpha_2"]&& A''\arrow[rr]&& 0
    \end{tikzcd}
\]

\end{document}