答案1
(更新将图片作为公式的一部分)
Tikz 可能对此有点过度,但很容易做到:
\documentclass{standalone}
\usepackage{tikz}
\usepackage{amsmath}
\usetikzlibrary{positioning}
\begin{document}
\begin{equation*}
\begin{tikzpicture}[baseline=(P.north)]
\node (G) {$\Gamma$};
\node[below=1.5ex of G] (P) {$\frac{\varphi}{p_0}$};
\draw (G.east) -- (P.north) -- (G.west);
\end{tikzpicture}
\in \text{DER}
\end{equation*}
\end{document}
答案2
以堆栈形式完成。
修改后的解决方案(带有尖头 V 形且少了一个封装):
\documentclass{article}
\usepackage{stackengine,graphicx}
\stackMath
\def\mystrut#1{\rotatebox[origin=c]{#1}{\rule{.4pt}{4ex}}}
\def\thinvee{\raisebox{-2pt}{\mystrut{45}\kern.8\dimexpr-.7071pt\mystrut{-45}}}
\begin{document}
\[
\stackunder[0pt]{\stackon[-4pt]{\thinvee}{\Gamma}}{\frac{\varphi}{~p_0~}}\in \textrm{DER}
\]
\end{document}
原始解决方案:
\documentclass{article}
\usepackage{stackengine,graphicx,xcolor}
\stackMath
\def\myvee{\raisebox{2pt}{\scalebox{3}[1.3]{$\bigvee$}}}
\def\thinvee{\stackengine{.5pt}{\myvee}{\color{white}\myvee}{O}{c}{F}{F}{L}}
\begin{document}
\[
\stackunder{\stackon[-5pt]{\thinvee}{\Gamma}}{\frac{\varphi}{~p_0~}}\in \textrm{DER}
\]
\end{document}