Rescaling \widecheck Accent

Question

This is essentially a repost of this question but for the \check symbol:

I would like to replace the usual \check in maths with a larger one, but I do not want it to stretch. The size I want is "the smallest \widecheck" (as in $\widecheck{.}$ ). Is there a way to put that one above a wide character like M ( $\widecheck{M}$ would stretch and give be an even wider check).

My main problem seems to be that I cannot find a corresponding symbol for \widecheck in the largesymbols font family.

Here is one workaround I was able to get. There is probably a simpler way.

\documentclass[12pt]{article}
\usepackage{amsmath,accents}
\DeclareFontShape{U}{mathx}{m}{n}{
          <5> <6> <7> <8> <9> <10>
          <10.95> <12> <14.4> <17.28> <20.74> <24.88>
          mathx10
          }{}
    \DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
    \DeclareFontSubstitution{U}{mathx}{m}{n}
    \DeclareMathAccent{\widecheck}{0}{mathx}{"71}
    \DeclareMathAccent{\wideparen}{0}{mathx}{"75}
\DeclareMathSymbol{\widechecksym}{\mathord}{mathx}{&quot;71}
\newcommand\lowerwidechecksym{%
  \text{\smash{\hspace*{-0.25ex}\raisebox{-1.1ex}{%
    $\widechecksym$}}}}
\newcommand\wcheck[1]{%
  \mathchoice
    {\accentset{\displaystyle\lowerwidechecksym}{#1}}
    {\accentset{\textstyle\lowerwidechecksym}{#1}}
    {\accentset{\scriptstyle\lowerwidechecksym}{#1}}
    {\accentset{\scriptscriptstyle\lowerwidechecksym}{#1}}
}


\DeclareMathSymbol{\widehatsym}{\mathord}{mathx}{&quot;70}
\newcommand\lowerwidehatsym{%
  \text{\smash{\hspace*{-0.25ex}\raisebox{-1.1ex}{%
    $\widehatsym$}}}}
\newcommand\what[1]{%
  \mathchoice
    {\accentset{\displaystyle\lowerwidehatsym}{#1}}
    {\accentset{\textstyle\lowerwidehatsym}{#1}}
    {\accentset{\scriptstyle\lowerwidehatsym}{#1}}
    {\accentset{\scriptscriptstyle\lowerwidehatsym}{#1}}
}


\end{document}

A wide check accent does not exist because it would be very problematic to understand what it refers to; the hat instead covers making usually clear what is its extent. On the other hand, I'd not recommend using very wide checks, for the same readability reason. — egreg, Dec 18 '20 at 22:44
@egreg Maybe I'm misunderstanding your comment, but \widecheck does exist as part of the mathx font family. I just haven't been able to get it working as in the linked post. — Mobius, Dec 18 '20 at 22:49

egreg · Accepted Answer · 2020-12-19T11:11:01.703

Do you mean this?

I find it awful and difficult to read, but you're the judge. Here's the code for importing the accent from mathabx.

\documentclass{article}
\usepackage{amsmath}
\DeclareFontFamily{U}{mathx}{}
\DeclareFontShape{U}{mathx}{m}{n}{ <-> mathx10 }{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\widecheck}{0}{mathx}{"71}
\begin{document}
$\check{a}\widecheck{aa}\widecheck{aaa}\widecheck{aaaa}\widecheck{aaaaa}$
\end{document}

If you just want the shortest wide check, the following code emulates the accent placement but is only apt for Latin letters. It could be extended also for Greek letters.

\documentclass{article}
\DeclareFontFamily{U}{mathx}{}
\DeclareFontShape{U}{mathx}{m}{n}{ <-> mathx10 }{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\widecheck}{0}{mathx}{"71}
\makeatletter
\newcommand{\wcheck}[1]{\mathpalette\wcheck@{#1}}
\newcommand{\wcheck@}[2]{%
  \begingroup
  \edef\wcheck@font{\the
    \ifx#1\displaystyle\textfont\else\ifx#1\textstyle\textfont
    \else\ifx#1\scriptstyle\scriptfont\else\scriptscriptfont\fi\fi\fi@ne
  }%
  \sbox\z@{\wcheck@font\mbox{#2}\mbox{\char\the\skewchar\font}}%
  \sbox\tw@{\wcheck@font#2\char\the\skewchar\font}%
  \dimen@=\dimexpr\wd\tw@-\wd\z@\relax
  {,\kern2\dimen@\widecheck{!\kern-2\dimen@#2!},}%
  \endgroup
}
\makeatother
\begin{document}
$\wcheck{M}$ $\wcheck{A}$
$\check{M}$ $\widecheck{A}$
\end{document}

In the example I use \check over M just to show that the accent placement is right.

\documentclass{article}
\DeclareFontFamily{U}{mathx}{}
\DeclareFontShape{U}{mathx}{m}{n}{ <-> mathx10 }{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\widecheck}{0}{mathx}{"71}
\makeatletter
\newcommand{\wcheck}[1]{\mathpalette\wcheck@{#1}}
\newcommand{\wcheck@}[2]{%
  \begingroup
  \edef\wcheck@font{\the
    \ifx#1\displaystyle\textfont\else\ifx#1\textstyle\textfont
    \else\ifx#1\scriptstyle\scriptfont\else\scriptscriptfont\fi\fi\fi@ne
  }%
  \sbox\z@{\wcheck@font\mbox{#2}\mbox{\char\the\skewchar\font}}%
  \sbox\tw@{\wcheck@font#2\char\the\skewchar\font}%
  \dimen@=\dimexpr\wd\tw@-\wd\z@\relax
  {,\kern2\dimen@\widecheck{!\kern-2\dimen@#2!},}%
  \endgroup
}
\makeatother
\begin{document}
$\wcheck{M}$ $\wcheck{A}$
$\scriptstyle\wcheck{M}\scriptstyle\check{M}$
$\scriptstyle\wcheck{A}\scriptstyle\widecheck{A}$
$\check{M}$ $\widecheck{A}$
\end{document}

An altogether different method is outlined below.

Copy mathx10.tfm to mathxy10.tfm in the working directory; on a Unix system with bash or similar shell,
```
cp $(kpsewhich mathx10.tfm) mathxy10.tfm
```
Convert the .tfm file into .pl
```
tftopl mathxy10.tfm > mathxy10.pl
```
Edit the file just created to find the entries with CHARACTER C p and CHARACTER C q to remove the NEXTLARGER property from both (just remove the line)
Convert the .pl file back to .tfm
```
pltotf mathxy10.pl
```

Add at the beginning of you TeX file the line

\pdfmapline{+mathxy10 TeX-mathx10 <mathx10.pfb}

Use the newly created font file as symbol font

Example

\pdfmapline{+mathxy10 TeX-mathx10 <mathx10.pfb}
\documentclass{article}
\DeclareFontFamily{U}{mathx}{}
\DeclareFontShape{U}{mathx}{m}{n}{ <-> mathxy10 }{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\what}{0}{mathx}{"70}
\DeclareMathAccent{\wcheck}{0}{mathx}{"71}
\begin{document}
$\wcheck{M}\wcheck{A}$
$\what{M}\what{A}$
\end{document}

These are the edits to do in the .pl file

Before

(CHARACTER C p
   (CHARWD R 0.55542)
   (CHARHT R 0.722046)
   (NEXTLARGER C x)
   )
(CHARACTER C q
   (CHARWD R 0.55542)
   (CHARHT R 0.722046)
   (NEXTLARGER O 174)
   )

After:

(CHARACTER C p
   (CHARWD R 0.55542)
   (CHARHT R 0.722046)
   )
(CHARACTER C q
   (CHARWD R 0.55542)
   (CHARHT R 0.722046)
   )

No. I want the \widecheck to always remain the same size, but be larger than \check. — Mobius, Dec 19 '20 at 00:05
@Mobius Added for Latin letters. I also add a different method. — egreg, Dec 19 '20 at 11:11
The first method seems to be working, but I really need it for Greek letters as well. Is this a simple fix? — Mobius, Dec 19 '20 at 19:46

Rescaling \widecheck Accent

1 Answers1