量词在 dfrac 旁边太小

Question

我想处理分数，将分数量化为单个元素，但\forall和\exists在附近显示得太小\dfrac。而且 mathlarger 似乎不起作用。

我只了解乳胶的基础知识，还没有找到任何可以解决这个问题的方法。

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{relsize}

\begin{document}
    \begin{enumerate}
        \item Neutral: $\mathlarger{\exists!} \dfrac{x}{y} : \dfrac{x}{y} + \dfrac{c}{d} = \dfrac{c}{d}$
    \end{enumerate}
\end{document}

Answer 1

也许你需要的是一个像大运算符一样的符号。请参阅以下代码和输出。

\documentclass{article}
\usepackage{amsmath}
\usepackage{scalerel}
\makeatletter
\DeclareMathOperator*{\bigexistsone}{\scalerel*{\exists!}{\sum}}
\makeatother

\begin{document}
\begin{enumerate}
\item The original one in text style in lines: $\exists!\dfrac{x}{y}\left(\dfrac{x}{y} + \dfrac{c}{d} = \dfrac{c}{d}\right)$, and the new one in display style between lines: $$\exists!\dfrac{x}{y}\left(\dfrac{x}{y} + \dfrac{c}{d} = \dfrac{c}{d}\right).$$
\item The new one in text style in lines: $\bigexistsone\dfrac{x}{y}\left(\dfrac{x}{y} + \dfrac{c}{d} = \dfrac{c}{d}\right)$, and the new one in display style between lines: $$\bigexistsone\dfrac{x}{y} \left(\dfrac{x}{y} + \dfrac{c}{d} = \dfrac{c}{d}\right).$$
\end{enumerate}

\end{document}