答案1
你能输入数据吗
\documentclass{article}
\usepackage{tikz-cd}
\begin{document}
\begin{tikzpicture}[commutative diagrams/every diagram]
\node (P0) at (180:2cm) {A};
\node (P1) at (90:2.3cm) {B} ;
\node (P2) at (-90:2cm) {C};
\node (P3) at (0:2cm) {D};
\path[commutative diagrams/.cd, every arrow, every label]
(P0) edge node[] {A1} (P1)
(P0) edge node[swap] {B1} (P2)
(P2) edge node [swap]{C1} (P3)
(P1) edge node {D1} (P3)
;
\end{tikzpicture}
\end{document}
答案2
作为起点:
\documentclass[margin=3.1415692mm,varwidth]{standalone}
\usepackage{tikz-cd}
\begin{document}
\[
\begin{tikzcd}[column sep=small]
& A \ar[dr,"k_*"] & \\
\pi_1(U\cap V,p) \ar[ur,"i_*"] \ar[dr,"j_*" ']
& & \pi_1(X,p). \\
& E \ar[ur,"l_*" '] &
\end{tikzcd}
\]
\[
\begin{tikzcd}[column sep=small]
& A \ar[d, hook]\ar[dr,"k_*"]
& \\
\pi_1(U\cap V,p) \ar[ur,"i_*"] \ar[dr,"j_*" ']
& \pi_1(U,p)*\pi_1(V,p) \ar[r,"\phi"]
& \pi_1(X,p). \\
& E \ar[u, hook']\ar[ur,"l_*" ']
&
\end{tikzcd}
\]
\end{document}
现在只需要用数学表达式替换 A 和 E。