# How to write geometric arcs notation without arcs package?

I've tried some other packages: yhmath and mathdesign, and some codes:

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


and

\def\frown{\XeTeXmathaccent"0"1"23DC}


These solutions haven't work at all, some mess up my other symbols like parenthesis, brackets and so on.

Is there a simple way to place an arc or similar over two or three letters?

I made it to here, after some comments and trying to figure it out, I made the arc symbol like this.

\renewcommand{\overarc}[1]{\ooalign{\hfil\scalebox{0.9}{$#1$}\hfil\cr\hfil\raisebox{8pt}{\rotatebox{90}{\scalebox{1}{$)$}}}\hfil\cr}}


It worked well for my proporses. but any suggestions are welcome.

Is this what you mean? It is based on my answer at Typesetting arc over the letter upside down

\documentclass{article}
\usepackage{scalerel}
\usepackage{stackengine}
\stackMath

\newcommand\reallywidefrown[1]{%
\stackon[0pt]{#1}{%
\stretchto{%
\scaleto{%
\scalerel*[\widthof{#1}]{\mkern-1.5mu\frown\mkern-2mu}%
{\rule[-\textheight/2]{1ex}{\textheight}}%
}{\textheight}%
}{0.8ex}}%
}
\parskip 1ex
\begin{document}

$\reallywidefrown{zbcdefghijklm}$

$\reallywidefrown{zbcdefghijk}$

$\reallywidefrown{zbcdefghi}$

$\reallywidefrown{zbcdefg}$

$\reallywidefrown{zbcde}$

$\reallywidefrown{zbc}$

$\reallywidefrown{zb}$

$\reallywidefrown{z} = 0$

\end{document}


If you require a version that preserves the math style, a less efficient version is available:

\documentclass{article}
\usepackage{scalerel}
\usepackage{stackengine}
\stackMath
\newsavebox\tmpbox
\newcommand\reallywidefrown[1]{\ThisStyle{%
\sbox\tmpbox{$\SavedStyle#1$}%
\stackon[0pt]{\usebox{\tmpbox}}{%
\stretchto{%
\scaleto{%
\scalerel*[\wd\tmpbox]{\mkern-.8mu\frown\mkern-.8mu}%
{\rule[-\textheight/2]{1ex}{\textheight}}%
}{\textheight}%
}{0.8ex}}%
}}
\parskip 1ex
\begin{document}

$\reallywidefrown{zbcdefghijklm} \quad\scriptstyle\reallywidefrown{zbcdefghijklm} \quad\scriptscriptstyle\reallywidefrown{zbcdefghijklm}$

$\reallywidefrown{zbcdefghijk} \quad\scriptstyle\reallywidefrown{zbcdefghijk} \quad\scriptscriptstyle\reallywidefrown{zbcdefghijk}$

$\reallywidefrown{zbcdefghi} \quad\scriptstyle\reallywidefrown{zbcdefghi} \quad\scriptscriptstyle\reallywidefrown{zbcdefghi}$

$\reallywidefrown{zbcdefg} \quad\scriptstyle\reallywidefrown{zbcdefg} \quad\scriptscriptstyle\reallywidefrown{zbcdefg}$

$\reallywidefrown{zbcde} \quad\scriptstyle\reallywidefrown{zbcde} \quad\scriptscriptstyle\reallywidefrown{zbcde}$

$\reallywidefrown{zbc} \quad\scriptstyle\reallywidefrown{zbc} \quad\scriptscriptstyle\reallywidefrown{zbc}$

$\reallywidefrown{zb} \quad\scriptstyle\reallywidefrown{zb} \quad\scriptscriptstyle\reallywidefrown{zb}$

$\reallywidefrown{z} = 0$

\end{document}