\begin{center}
\begin{tikzpicture}
\node (E) at (0,0) {$E|_U:=\pi^{-1}(U)$};
\node[right=of E] (F) {$U\times F$};
\draw[->] (E)--(F) node [midway,above] (phi) {$\Phi$};
\node[below= 1cm of phi] (A) {$U$};
\draw[->] (E)--(A.north west) node [midway,below] {$\pi$};
\draw[->] (F)--(A.north east) node [midway,right] {$\pi_1$};
\draw [<-] ([yshift=2mm]A.north) arc[start angle=-90,delta angle=270,radius=0.25cm];
\end{tikzpicture}
\end{center}
答案1
tikz-cd
如果您提到您有上一个问题的图表代码,那就太好了。
tikz-cd
创建一个matrix of nodes
放置元素的单元格。通过添加,every matrix/.append style={name=M}
您可以使用M-m-n
来引用特定单元格,其中m
是行号,n
是列号(反之亦然,我永远记不住)。然后您可以使用 来execute at end picture
绘制相对于底部中间单元格的箭头。
\documentclass{article}
\usepackage{tikz-cd,amsmath}
\usepackage{amsfonts}
\begin{document}
\[
\begin{tikzcd}[every matrix/.append style={name=m},
execute at end picture={
\draw [<-] ([yshift=2mm]m-2-2.north) arc[start angle=-90,delta angle=270,radius=0.25cm];
}]
E|_U:=\pi^{-1}(U)\arrow[rr,"\Phi" ]\arrow[dr,swap,"\pi" ]& & U\times \mathbb{R}^k \arrow[dl,"\pi_1" ] \\
& U &
\end{tikzcd}
\]
\end{document}