答案1
类似这种类型的东西吗?
\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb}
\begin{document}
\[
U=\left\{ (u,v) \;\middle\vert\;
\begin{array}{@{}l@{}}
u, v\colon \mathbb{R}^d\to[0,\infty) \\
\text{bla bla bla}\\
u+v<7
\end{array}
\right\}
\]
\end{document}
答案2
另一个解决方案,基于\DeclarePairedDelimiterX
frommathtools
和``xparse`` 实现自然语法(我的意思是接近手写的语法):
\documentclass{article}
\usepackage{amssymb}
\usepackage{mathtools}
\usepackage{xparse}
\DeclarePairedDelimiterX{\Set}[1]\{\}{\setargs{#1}}
\NewDocumentCommand{\setargs}{>{\SplitArgument{1}{|}}m}
{\setargsaux#1}
\NewDocumentCommand{\setargsaux}{mm}
{\IfNoValueTF{#2}{#1}{\nonscript\,#1\nonscript\;\delimsize\vert\allowbreak \nonscript\:\mathopen{}#2\nonscript\,}}
\begin{document}
\[ \Set*{(u, v) | \begin{array}{@{}l@{}}
u, v: \mathbb{R}^d ―――→ [0,∞)\\[-0.5ex]
\text{upper semi-continuous} \\[-0.5ex]
u + v < 7
\end{array}} \]%
\end{document}