frown and mathop/stackrel/overset

Question

I need something like \stackrel{\frown}{MM'} to express the fact that MM' is some path. But I am not really satisfied by the look of the result. The \frown is too high. Would you please have a suggestion?

Edit 1: I just discovered that the font I'm using, ie kpfonts, offers a nice widearc command which suits my needs.

Answer 1

You may try \wideparen from the yhmath package:

\usepackage{yhmath}
...
$\wideparen{MM'}$

In case you don't want to change the largesymbol font, it's possible to load only the \wideparen accent:

\documentclass{article}
\DeclareSymbolFont{yhlargesymbols}{OMX}{yhex}{m}{n}
\DeclareMathAccent{\wideparen}{\mathord}{yhlargesymbols}{"F3}

\begin{document}
$\wideparen{MM'}$
\end{document}

Answer 2

You can use arcs package for this. It provides the \overarc command. But this package seems to be broken on my computer. :(

You can also use \wideparen provided by yhmath font package. yhmath is compatible with default CM fonts.

\documentclass{article}
\usepackage{yhmath}

\begin{document}
$\wideparen{MM'}$
\end{document}

MnSymbol package, mathdesign package, and maybe some other math font packages, also provide \wideparen. It would be great if you use MinionPro with MnSymbol, or Utopia with mathdesign fonts.

For example:

\documentclass{article}
\usepackage[utopia]{mathdesign}

\begin{document}
$\wideparen{MM'}$
\end{document}

Answer 3

Although this question is quite old, here’s a solution using TikZ:

\documentclass{article}

\usepackage{parskip}

\usepackage{tikz}
   \usetikzlibrary{calc}

\newcommand{\overbow}[1]{
   \tikz [baseline = (N.base), every node/.style={}] {
      \node [inner sep = 0pt] (N) {$#1$};
      \draw [line width = 0.4pt] plot [smooth, tension=1.3] coordinates {
         ($(N.north west) + (0.1ex,0)$)
         ($(N.north)      + (0,0.5ex)$)
         ($(N.north east) + (0,0)$)
      };
   }
}

\begin{document}
$ABC$ $\overline{ABC}$ $\overbow{ABC}$

$\overline{AB}$ $\overbow{AB}$

$\overline{MC}$ $\overbow{MC}$

$\overline{HA}$ $\overbow{HA}$

$\overline{AH}$ $\overbow{AH}$

$A \overline{A} \overbow{A}$

$xgfx \overline{gf}x \overbow{gf}x$
\end{document}

To use it with other fonts, the line width and shifting values may have to be adapted.

Answer 4

In ConTeXt, this accent is provided by \overparent:

\starttext
$\overparent{MMM}$

\startformula
  \int_{\overparent{MM'}} f(x) dx
\stopformula

\stoptext

which gives

Answer 5

Accent seems like a way to go (example with XITS and XeTeX, in Plain):

\def\frown{\XeTeXmathaccent"0"1"23DC}
$$ \frown{MM'} \int\limits_{\frown{MM'}} $$
\bye

Answer 6

I don't know if in practice (I'm not mathematician, sorry) someone will need ever arcs wider than 4 or 5 lowercase characters. If this could be a real scenario, then \widearc of kpfonts, or \wideparen of yhmath or mathdesign, or \bigfrown, probably are not the best solution, since like others extensible accents, are unable to expand too much:

This problem seem well solved with \overparent in Aditya answer, but this require ConTeX. For pdflatex, I think that a decent alternative could be \overgroup from mathabx package:

\documentclass{minimal}
\usepackage{mathabx}
\begin{document}
$\overgroup{M'}$
$\overgroup{MM'}$
$\overgroup{MMMM'}$
$\overgroup{MMMMMMMM'}$
\end{document}

Answer 7

\documentclass{article}
\usepackage{graphicx,amsmath}
\newcommand\bigfrown[2][\textstyle]{\ensuremath{%
  \array[b]{c}\text{\scalebox{2}{$#1\frown$}}\\[-1.3ex]#1#2\endarray}}

\begin{document}

foo \bigfrown{MM'} bar

\[\int\limits_{\protect\bigfrown[\scriptstyle]{MM'}}\]

\end{document}

Answer 8

from fourier added in preamble

\DeclareFontEncoding{FMX}{}{}%%%
\DeclareFontSubstitution{FMX}{futm}{m}{n}%%%
\DeclareSymbolFont{largesymbols}{FMX}{futm}{m}{n}
\DeclareMathAccent{\widearc}{\mathord}{largesymbols}{216}

Use

\[\widearc{MM'} + \int\limits_{\widearc{MM'}}\]