答案1
在这里查看矩阵库示例:http://www.texample.net/tikz/examples/commutative-diagram-tikz/
\documentclass[tikz]{standalone}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes,row sep=3em,column sep=4em,minimum width=2em]
{
A & B \\
A/ker f & f(A) \\};
\path[-stealth]
(m-1-1) edge node [left] {$p_{ker f}$} (m-2-1)
edge node [above] {$f$} (m-1-2)
(m-2-2) edge node [right] {$i$} (m-1-2)
(m-2-1) edge [dashed] node [above] {$\bar{f}$} (m-2-2);
\end{tikzpicture}
\end{document}