我正在尝试复制下图,有人能帮我吗?乳胶代码如下
Let $A$ and $B$ be rings, where $B$ is an $A$-module.
If
\[
(a\cdot x)\underset{B}{\cdot}(b\cdot y)=(a\underset{A}{\cdot} b)\cdot(x\underset{B}{\cdot} y),\, \forall a,b\in A\textrm{ and }x,y\in B
\]
then $\phi:A\rightarrow B$ is a ring homomorphism and the structure of $B$ as $A$-module via $\phi$ is the original structure of $B$ as $A$-module.
如果我使用下划线,它看起来很糟糕。
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答案1
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{tikzmark}
\usepackage{amsmath}
\newcommand{\tmn}{\tikzmarknode}
\begin{document}
\[
(a\tmn{A}{\cdot} x)\underset{B}{\cdot}(b\tmn{B}{\cdot} y)=(a\underset{A}{\cdot} b)\tmn{C}{\cdot}(x\underset{B}{\cdot} y),\, \forall a,b\in A\textrm{ and }x,y\in B
\]
\begin{tikzpicture}[overlay,remember picture,every path/.style={->}]
\draw (A) --++ (0,-1) node[below] {Comment 1};
\draw (B) --++ (0,-2) node[below] {Comment 2};
\draw (C) --++ (0,-1) node[below] {Comment 3};
\end{tikzpicture}
\end{document}
至于装饰(如果确实需要的话),您可以自己选择最喜欢的。请注意,您必须至少编译两次才能获得最终结果tikzmark
。