Two dotted division symbol

Question

I'm making a report about progression in another language. Is there any way to make two dotted (both up and low) ÷ symbol?

I have searched in many things and i can't find it.

Answer 1

There is a Unicode symbol:

∺ U+223A Geometric proportion

LuaTeX/XeTeX

The Unicode math fonts for LuaTeX or XeLaTeX usually contain this symbol:

\documentclass{article}
\usepackage{unicode-math}
\setmathfont{xits-math.otf}

\begin{document}
\newcommand*{\test}[2]{%
  #1&%
  \setmathfont{#1}% or via font name #2
  $\dotsminusdots\div$%
}
\begin{tabular}{lc}
  \test{Latin Modern Math}{latinmodern-math.otf}\\
  \test{Asana Math}{Asana-Math.otf}\\
  \test{XITS Math}{xits-math.otf}\\
  \test{TeX Gyre Bonum Math}{texgyrebonum-math.otf}\\
  \test{TeX Gyre Pagella Math}{texgyrepagella-math.otf}\\
  \test{TeX Gyre Schola Math}{texgyreschola-math.otf}\\
  \test{TeX Gyre Termes Math}{texgyretermes-math.otf}\\
\end{tabular}
\end{document}

Poor man's version

The following example constructs the symbol from the minus sign and the dot:

• The symbol automatically follows the math style with its size.

• It is assumed that the side bearings are the same for the minus sign and the dot. Then the dots and the ends of the minus sign will be aligned correctly.

• The bottom dots are put on the base line.

• The minus on the math axis is a mirror axis for the dots, if the character bounding box for the dot is correct, especially its height.

Depending on the math font, the dots in symbol \div might differ, e.g. larger than the normal dot or greater distance from the horizontal line.

\documentclass{article}

\makeatletter
\providecommand*{\dotsminusdots}{%
  \mathrel{%
    \mathpalette\@dotsminusdots{}%
  }%
}
\newcommand*{\@dotsminusdots}[2]{%
  % #1: math style
  % #2: unused
  \sbox0{$#1\vcenter{}$}% \ht0: math axis
  \sbox2{$#1.\m@th$}% \ht2: height of dot
    % Character bounding box of \cdot is wrong
    % in some fonts (e.g., Computer Modern)
  \sbox4{%
    \raise\dimexpr2\ht0-\ht2\rlap{\unhcopy2}%
    \unhcopy2 %
  }%
  \rlap{\unhcopy4}%
  {-}%
  \llap{\unhcopy4}%
}
\makeatother

\begin{document}
\[
  x \dotsminusdots y_{x \dotsminusdots y_{x \dotsminusdots y}}
\]
\end{document}

Answer 2

I assume you want this as a binary operator. Then the following will work at different sizes.

\documentclass{article}

\newcommand{\ddiv}{\mathbin{{\div}\mkern-10mu{\div}}}

\begin{document}

\( A \div B \ddiv C ^ {D \div E \ddiv F^{G \div H \ddiv I}} \)

\end{document}

Answer 3

Here's one way, with stacks. If you need it with different kerning, or to work in script style or scriptscriptstyle, see below.

\documentclass{article}
\usepackage{stackengine}
\stackMath
\def\ddiv{\mathop{\stackunder[-1.6pt]{\stackon[-1.6pt]{-\kern-6.5pt-}{..}}{..}}}
\begin{document}
$A\div B\ddiv A$

$A\ddiv B\div A$
\end{document}

If you wanted the dots to be of a comparable size to those of the \div symbol, then this variation would work:

\documentclass{article}
\usepackage{stackengine,graphicx}
\stackMath
\def\DD{\scalebox{1.2}{.}\scalebox{1.2}{.}}
\def\ddiv{\mathop{\stackunder[-1.8pt]{\stackon[-1.8pt]{-\kern-6.5pt-}{\DD}}{\DD}}}
\begin{document}
$A\div B\ddiv A$

$A\ddiv B\div A$
\end{document}

If you want it to scale to different mathstyles, here is an option:

\documentclass{article}
\usepackage{stackengine,graphicx,scalerel}
\stackMath
\def\DD{\scalebox{1.2}{$\SavedStyle.$}%
  \kern-2pt\kern2\LMpt\scalebox{1.2}{$\SavedStyle.$}}
\def\ddiv{\mathop{\ThisStyle{\stackunder[-.8pt-\LMpt]{%
  \stackon[-.8pt-\LMpt]{%
  \SavedStyle-\kern-4pt\kern-2.5\LMpt-}{\DD}}{\DD}}}}
\begin{document}
$A\div B\ddiv A$\par
$A\ddiv B\div A$\par
$\scriptstyle A\ddiv B$\par
$\scriptscriptstyle A\ddiv B$\par
\end{document}

...or with altered kerning more in line with the unicode symbols:

\documentclass{article}
\usepackage{stackengine,graphicx,scalerel}
\stackMath
\def\DD{\scalebox{1.2}{$\SavedStyle.$}%
  \kern-2pt\kern4\LMpt\scalebox{1.2}{$\SavedStyle.$}}
\def\ddiv{\mathop{\ThisStyle{\stackunder[-.8pt-\LMpt]{%
  \stackon[-.8pt-\LMpt]{%
  \SavedStyle-\kern-4pt\kern-2.5\LMpt-}{\DD}}{\DD}}}}
\begin{document}
$A\div B\ddiv A$\par
$A\ddiv B\div A$\par
$\scriptstyle A\ddiv B$\par
$\scriptscriptstyle A\ddiv B$\par
\end{document}