答案1
以下是使用\vdotswithin
命令的两个可能解决方案,来自mathtools
。第二个解决方案需要empheq
(加载mathtools
):
\documentclass{article}
\usepackage{empheq}
\begin{document}
\begin{equation}
\begin{cases}
\begin{aligned}
S_0&=\{1,2,3,4\}\\
S_1&=\{1,2,3,4,5,6,7,8 \}\\
S_2&=\{1,2,3,4,5,6,7,8,9,10,11,12\}\\
&\vdotswithin{=}
\end{aligned}
\end{cases}
\end{equation}
or, with a shorter spacing:
\begin{empheq}[left=\empheqlbrace]{align*}
S_0&=\{1,2,3,4\}\\
S_1&=\{1,2,3,4,5,6,7,8 \}\\
S_2&=\{1,2,3,4,5,6,7,8,9,10,11,12\}\\
&\shortvdotswithin{=}
\end{empheq}
\end{document}