如何得到符号丢番图减号

Question

我需要丢番图减号 (https://sites.math.rutgers.edu/~cherlin/History/Papers2000/kirschm.html）

Answer 1

如果你找不到该符号，你可以随时在 TikZ 中绘制它：

\documentclass[margin=1mm]{standalone}

\usepackage{amsmath}

\usepackage{tikz}
\usetikzlibrary{arrows.meta}
\DeclareMathOperator{\foo}{\tikz[
  baseline={(0,0.02ex)},
  line width=0.13ex,
  looseness=1.5,
  line cap=round
]{
  \draw (0,0) -- (0,1.1ex);
  \draw (-0.8ex,0.9ex) to[out=-60,in=180,in looseness=0.6] (0,1.1ex) to[out=0,in=-120,out looseness=0.6] (0.8ex,0.9ex);
}}

\begin{document}
$
  a \foo b
$
\end{document}