# Dashed underline under a inequality symbol

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:

• Excuse me but it's just a curiosity. But where is this symbol used in Mathematics? – Sebastiano Aug 14 '18 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 '18 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}


• Upvote surely. I have asked at the OP where this symbol is used in Mathematics ambient. – Sebastiano Aug 14 '18 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}


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}


• You've been very good at hiding the horizontal line with white dots. +1. – Sebastiano Aug 14 '18 at 20:22
• @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 '18 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}


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.

Here there is my spartan proposal.

\documentclass{article}
\usepackage{amssymb, amsmath,graphics}
\usepackage{stackengine}
\newcommand\newgeq[1]{\stackunder[0.8pt]{$#1$}{{{\hspace{.03cm}\scalebox{0.4}\mathunderscore} {\hspace{-.1cm}\scalebox{0.4}\mathunderscore} {\hspace{-.1cm}\scalebox{0.4}\mathunderscore}}}}
\begin{document}

$\newgeq{a>b}$
\end{document}