I'm trying to find (or create) a symbol that is like \geq but with a dashed/dotted line under the inequality symbol. It should look like this:

enter image description here

Thanks in advance

  • 1
    Excuse me but it's just a curiosity. But where is this symbol used in Mathematics? – Sebastiano Aug 14 at 20:23
  • I use this symbol to say that the inequality could be strict or not. I could also use round brackets on the equal, under the > symbol but this could be more complicated i suppose. – Paolo Aug 14 at 20:32

Some dirty tricks with low level programming and picture mode.

\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e,picture}

\makeatletter
\newcommand{\dashedeq}[1]{\mathrel{\vphantom{\geq}\mathpalette\dashed@eq{#1}}}
\newcommand{\dashed@eq}[2]{%
  \vcenter{%
    \offinterlineskip
    \roundcap
    \linethickness{1.2\dimexpr\variable@rule{#1}\relax}%
    \sbox\z@{$\m@th#1#2$}%
    \setlength{\unitlength}{\dimexpr(\wd\z@-2\dimexpr\dashed@eq@kern{#1})/8}%
    \sbox\tw@{\begin{picture}(1,0)\Line(0,0)(1,0)\end{picture}}%
    \ialign{%
      ##\cr
      \copy\z@\cr
      \noalign{\vskip 0.3\ht\z@}
      \kern\dashed@eq@kern{#1}%
      \copy\tw@\hfil\copy\tw@\hfil\copy\tw@\hfil\copy\tw@
      \kern\dashed@eq@kern{#1}%
      \cr
    }%
  }%
}
\newcommand{\dashed@eq@kern}[1]{%
  \ifx#1\displaystyle 0.12\wd\z@\else
    \ifx#1\textstyle 0.12\wd\z@\else
      \ifx#1\scriptstyle 0.14\wd\z@\else
        0.16\wd\z@
  \fi\fi\fi
}
\newcommand{\variable@rule}[1]{%
  \fontdimen8  
  \ifx#1\displaystyle\textfont3\else
    \ifx#1\textstyle\textfont3\else
      \ifx#1\scriptstyle\scriptfont3\else
        \scriptscriptfont3\relax
  \fi\fi\fi
}
\makeatother

\DeclareRobustCommand{\geqd}{\dashedeq{>}}
\DeclareRobustCommand{\leqd}{\dashedeq{<}}

\begin{document}

$a\ge b\geqd c\leqd d$

$\scriptstyle a\ge b\geqd c\leqd d$

$\scriptscriptstyle a\ge b\geqd c\leqd d$

\end{document}

enter image description here

  • Upvote surely. I have asked at the OP where this symbol is used in Mathematics ambient. – Sebastiano Aug 14 at 20:25

WITH WHITE RULES

\documentclass{article}
\usepackage{stackengine,xcolor,scalerel}
\def\shp{\shprule\kern.6\LMpt\kern.25pt}
\def\shprule{\rule{.5\LMpt}{1\LMpt}}
\def\dashle{\mathrel{\ThisStyle{\ensurestackMath{\stackengine{%
  -.8\LMpt}{\SavedStyle\le}{\scriptscriptstyle\color{white}%
  \shp\shp\shp\shprule}{U}{c}{F}{F}{S}}}}}
\begin{document}
$a \dashle b$

$\scriptstyle a \dashle b$

$\scriptscriptstyle a \dashle b$
\end{document}

enter image description here

WITH WHITE DOTS

\documentclass{article}
\usepackage{stackengine,xcolor,scalerel}
\def\shp{.\kern-1.9pt\kern.9\LMpt}
\def\dashle{\mathrel{\ThisStyle{\ensurestackMath{\stackengine{%
  \dimexpr-.47pt+.02\LMpt\relax}{\SavedStyle\le}{%
  \scriptscriptstyle\color{white}\shp\shp\shp.}{U}{c}{F}{F}{S}}}}}
\begin{document}
$a \dashle b$

$\scriptstyle a \dashle b$

$\scriptscriptstyle a \dashle b$
\end{document}

enter image description here

  • You've been very good at hiding the horizontal line with white dots. +1. – Sebastiano Aug 14 at 20:22
  • 1
    @Sebastiano Thanks! The challenge is that the smaller math styles are not direct scales of the larger and so some dimensions have to be taken as linear combinations of a non-scaling distance pt and a scalable distance \LMpt. Thus, something like \dimexpr-.47pt+.02\LMpt\relax is needed to work across all 3 math styles. – Steven B. Segletes Aug 15 at 0:19

I assume you have already tried detexify and are aware of How to look up a symbol or identify a math symbol or character?. I have not found your symbol by myself. You could either use a different symbol (https://ctan.org/pkg/unicode-math provides some symbols) or use various tools to construct your own. Here is an quick and dirty solution which uses https://www.ctan.org/pkg/pgf to add some blank space to the \geq symbol.

\documentclass{memoir}
\usepackage{tikz,xcolor,amsmath}
\usetikzlibrary{calc}
\newcommand{\dashgeq}{\tikz[baseline=(dashgeqanchor.base)]{
    \node (dashgeqanchor) {$\geq$}; 
    \draw[color=white,line width=0.05em] 
        (dashgeqanchor.base) -- +(0,-0.25em) 
        ($(dashgeqanchor.base) + (0.175em,0)$) -- +(0,-0.25em) 
        ($(dashgeqanchor.base) - (0.175em,0)$) -- +(0,-0.25em); 
}}

\begin{document}
\begin{align*}
    6   &> 5\\
    6   &\dashgeq 5\\
    6   &\geq 5
\end{align*}
\tiny
\begin{align*}
    6   &> 5\\
    6   &\dashgeq 5\\
    6   &\geq 5
\end{align*}
\huge
\begin{align*}
    6   &> 5\\
    6   &\dashgeq 5\\
    6   &\geq 5
\end{align*}
\end{document}

enter image description here

Notes

  • This version works on white background only.
  • A savebox might be useful if the symbol is frequently used in the same size.
  • The constants chosen in the code are just found by a simple heuristics and might not work well if you use other math fonts.
  • Other ideas might be found in Create symbol out of given symbols with same line width.
  • The two outer edges of the dashed line are round whereas the inner are not.

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