答案1
我建议您加载该mathtools
包的dcases*
环境和宏。并且,请对方括号内的列向量\coloneqq
使用环境。bmatrix
\documentclass{article}
\usepackage{mathtools} % for dcases* env. and \coloneqq macro
\begin{document}
\[
G_{\chi}(\eta) \coloneqq
\begin{dcases*}
\bigl(
[T_{u,1}^*, T_{u,2}^*],\tau_y,0,\eta_c
\bigr)
& if $\tau_u=0$ and $\tau_y>0$ \\[\jot]
\bigl(
\tau_u,[T_{y,1}^*, T_{y,2}^*],0,F_c^s(\eta)
\bigr)
& if $\tau_u>0$ and $\tau_y=0$ \\[\jot]
\left\{
\begin{bmatrix}
[T_{u,1}^*, T_{u,2}^*] \\ \tau_y \\ 0 \\ \eta_c
\end{bmatrix},
\begin{bmatrix}
\tau_u \\ [T_{y,1}^*, T_{y,2}^*] \\ 0 \\F_c^s(\eta)
\end{bmatrix}
\right\}
& if $\tau_u=0$ and $\tau_y=0$
\end{dcases*}
\]
\end{document}
答案2
出发点可以是
\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
X =
\begin{cases}
\begin{Bmatrix}
\begin{bmatrix}
a & b\\
c & d
\end{bmatrix}
,
\begin{bmatrix}
A & B\\
D & C
\end{bmatrix}
\end{Bmatrix}
& \text{if $x=p$} \\
0 & \text{otherwise}
\end{cases}
\end{equation*}
\end{document}