答案1
\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}
\begin{document}
\[\begin{tikzcd}[column sep=0pt,nodes={inner xsep=0pt,outer xsep=0pt}]
\{\text{category of $A$--modules}\}=\, & \mathcal{C}\arrow[d] & \qquad & M \arrow[d,mapsto]\\
\{\text{category of $B$--modules}\}=\, & \mathcal{D} & \qquad & B\otimes_A M\\
\end{tikzcd}\]
\end{document}
带边缘标签:
\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}
\begin{document}
\[\begin{tikzcd}[column sep=0pt,nodes={inner xsep=0pt,outer xsep=0pt}]
\{\text{category of $A$--modules}\}=\, & \mathcal{C}\arrow[d,"f" swap] & \qquad & M
\arrow[d,mapsto,"f"]\\
\{\text{category of $B$--modules}\}=\, & \mathcal{D} & \qquad & B\otimes_A M\\
\end{tikzcd}\]
\end{document}
答案2
\documentclass[a4paper,12pt]{article}
\usepackage[all]{xy}
\usepackage{amsmath,amssymb}
\begin{document}
\xymatrix{
*\txt{$\{$category of $A$--modules$\}$}&\mkern-20mu=e\ar[d]& M\ar@{|-{>}}[d]\\
*\txt{$\{$category of $B$--modules$\}$}&\mkern-20mu=\mathcal{D} & B\otimes_A M
}
\end{document}
答案3
array
具有两次旋转的简单示例:
\documentclass{article}
\usepackage{amsmath,graphicx}
\begin{document}
\[
\renewcommand{\arraystretch}{1.5}
\begin{array}{@{} r @{} c c @{}}
\{\text{category of $A$-modules}\}={} & \mathcal{C} & M \\
& \rotatebox[origin=c]{-90}{$\longrightarrow$}
& \rotatebox[origin=c]{-90}{$\longmapsto$} \\
\{\text{category of $B$-modules}\}={} & \mathcal{D} & B \otimes_A M
\end{array}
\]
\end{document}