答案1
前往网页https://detexify.kirelabs.org/classify.html并绘制符号。分类器会告诉你这是\rightthreetimes
来自amssymb
包的符号。
\documentclass{article}
\usepackage{amsmath}% \begin{cases} ... \end{cases}
\usepackage{amssymb}% \rightthreetimes
\begin{document}
\[
\begin{cases}
d_\rightthreetimes\geq a, d_\rightthreetimes\geq b, d_\rightthreetimes\geq c\\
a + b + c \geq 2d_\rightthreetimes\\
a + b + c \leq 2
\end{cases}
\]
\end{document}
答案2
您可以使用\mathpalette
(您可以在网站上找到几个示例)。
\documentclass{article}
\usepackage{graphicx}
\makeatletter
\DeclareRobustCommand{\mlambda}{% mirror lambda
{\mathpalette\mlambda@\relax}%
}
\newcommand{\mlambda@}[2]{%
\reflectbox{$\m@th#1\lambda$}%
}
\makeatother
\begin{document}
$\mlambda+x_{\mlambda}$
$\lambda+x_{\lambda}$
\end{document}