4

I want to combine the existential and universal quantifiers so that the left part of the universal quantifier match the right of the existential.

To do so I defined the command:

\newcommand{\quantifs}{\exists\hspace{-3.1pt}\resizebox{7.45pt}{!}{\rotatebox[origin=c]{-20}{$\forall$}}}

Which work well when I type $\quantifs$. However the matching gets all wrong if the sizes change, for example when it is in subscript like in $x_{\quantifs}$.

How can I fix that? Or is there already such symbol defined somewhere?

7

For a geometric symbol it's better to use geometry. ;-)

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

\newcommand{\quantifs}{\mathpalette\xquantifs\relax}

\makeatletter
\newcommand{\xquantifs}[2]{%
  \mspace{1.5mu}%
  \sbox0{$\m@th#1\exists$}%
  \setlength{\unitlength}{.8\ht0}%
  \ifx#1\scriptstyle\linethickness{0.35pt}\fi
  \ifx#1\scriptscriptstyle\linethickness{0.3pt}\fi
  \begin{picture}(1.55,1.2)
  \roundcap\roundjoin
  \polyline(0,0.05)(0.75,0.05)(0.75,1.22)(0,1.2)
  \polyline(0.05,0.625)(0.75,0.625)
  \put(0.75,0.05){\line(5,6){0.8}}
  \put(0.75,0.85){\line(11,-5){0.45}}
  \end{picture}%
  \mspace{1.5mu}
}
\makeatother

\begin{document}

$\exists\quantifs\exists$

$\scriptstyle\exists\quantifs\exists$ $x_{\exists}x_{\quantifs}$

$\scriptscriptstyle\exists\quantifs\exists$

\end{document}

enter image description here

In scriptscript style the reversed E is not as wide as in \exists; this could be fixed, if really needed.

| improve this answer | |
  • Thanks a lot!! I was getting a bit irritated with the scale and rotate thing ... That's really helpful! Thanks again! – wece May 29 '15 at 12:41
  • @wece The angle at the vertex of the reversed A (\forall) is different in subscript style, so a choice could have been defining different angles for the different styles, but there were also other problems, including different side bearings. So I thought it better to do some measuring and using picture. – egreg May 29 '15 at 12:46
  • @wece I made a little fix to get the line thickness even. In second level subscripts the width is not precise, tell me if you need a fix. – egreg May 29 '15 at 12:53
  • @egreg Small note: I don't think the counter of the A in the \forall part is actually isosceles. Needs some fine-tuning (or some basic maths). Of course, I may be wrong and this is some optical illusion -- I haven't exactly taken any measurements XD – Sean Allred May 29 '15 at 14:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.