答案1
您可以使用aligned
(或array
):
\documentclass{article}
\usepackage{amsmath}
\usepackage{mathrsfs}
\begin{document}
This is over two lines
\begin{equation}
\left\{
\langle x,y\rangle \;\middle|\;
\begin{aligned}
& x\in p^1_{ij}(\mathscr{H}),\lVert x\rVert =1,\\
& y\in p^1_{kl}(\mathscr{H}),\lVert y\rVert=1
\end{aligned}
\right\}
\end{equation}
and this is on the same line, which I find clearer
\begin{equation}
\{
\langle x,y\rangle \mid
x\in p^1_{ij}(\mathscr{H}),\lVert x\rVert =1,
y\in p^1_{kl}(\mathscr{H}),\lVert y\rVert=1
\}
\end{equation}
or, as well,
\begin{equation}
\{
\langle x,y\rangle \mid
x\in p^1_{ij}(\mathscr{H}),
y\in p^1_{kl}(\mathscr{H}),
\lVert x\rVert =1,
\lVert y\rVert=1
\}
\end{equation}
\end{document}
命令\vert
不适用于集合符号中的条形,应使用\mid
。还应\Vert
区分为\lVert
和\rVert
(同样,对于绝对值,它比 更好\lvert...\rvert
)|...|
。