# Circle above a letter

I could write a circle above the letter but it seems far a little bit

Is there a way to get it down a little bit, because I really use it a lot and it takes a lot of space. Here is a sample of the code:

\documentclass[twoside]{article}
\usepackage{fancyhdr}
\usepackage{nameref}
\usepackage{abraces}
\usepackage{amsfonts,amsmath, amssymb, mathtools}
\makeatletter
\newcommand*{\currentname}{\@currentlabelname}
\makeatother

\fancypagestyle{yourStyle}{
\fancyhf{}
}

\begin{document}

$$\left((\overline{M})_{\tau_1}\right)^\mathsf{c} = (\aoverbrace[L1R] {M^\mathsf{c}}^{\circ})_{\tau_1}$$
$$\left((\overline{M})_{\tau_2}\right)^\mathsf{c} = (\aoverbrace[L1R] {M^\mathsf{c}}^{\circ})_{\tau_2}$$

• What maths or physics notation is this? What does it mean? – smci Jul 28 at 6:22
• @smci I do not know about physics this is related to mathematics, and it means the interior of a set. – Tarek Acila Jul 28 at 11:28

Perhaps with the use of stacks. The current \circ elevation is controlled by the -2pt optional argument to \stackon.

\documentclass{article}
\usepackage{abraces}
\usepackage{amsfonts,amsmath, amssymb, mathtools}
\usepackage{stackengine}
\stackMath
\begin{document}
$\left((\overline{M})_{\tau_1}\right)^\mathsf{c} = (\stackon[-2pt]{\aoverbrace[L1R] {M^\mathsf{c}}}{\scriptstyle\circ})_{\tau_1}$
$\left((\overline{M})_{\tau_2}\right)^\mathsf{c} = (\stackon[-2pt]{\aoverbrace[L1R] {M^\mathsf{c}}}{\scriptstyle\circ})_{\tau_2}$
\end{document}


You can even make it a macro:

\documentclass{article}
\usepackage{abraces}
\usepackage{amsfonts,amsmath, amssymb, mathtools}
\usepackage{stackengine}
\newcommand\bracecirc[1]{%
\ensurestackMath{\stackengine{-2pt}
{\aoverbrace[L1R]{#1}}{\scriptstyle\circ}{O}{c}{F}{F}{S}}%
}
\begin{document}
$\left((\overline{M})_{\tau_1}\right)^\mathsf{c} = (\bracecirc{M^\mathsf{c}})_{\tau_1}$
$\left((\overline{M})_{\tau_2}\right)^\mathsf{c} = (\bracecirc{M^\mathsf{c}})_{\tau_2}$
\end{document}

• This is exactly what I was looking for!! Thank you so much – Tarek Acila Jul 27 at 12:13
• @TarekAcila You are welcome. I edited the macro form definition, to make it impervious to changes in stackengine defaults elsewhere in the document. That is, you can change defaults for stackengine if your document has different uses for it, without breaking this macro definition. – Steven B. Segletes Jul 27 at 12:26

I have changed the initial code completely: there are the combination of two particular packages: accents and scalerel. With these packages I have created a macro called \arcsup with the arc only above the character . If you want to have a large horizontal arc you can increase the value of \hstretch{1.8} to stretch horizzontally the arc.

\documentclass[a4paper,12pt]{article}
\usepackage{amssymb,mathtools}
\usepackage{accents}
\usepackage{scalerel}
\newcommand\arcsup[1]{\accentset{\overset{\scriptscriptstyle\circ}{\hstretch{1.8}{\frown}}}{#1}}
\begin{document}

$\bigl((\overline{M})_{\tau_1}\bigr)^{\!\mathsf{c}} = (\arcsup{M}^\mathsf{c})_{\tau_1}$
\end{document}


You can see the increment to

\hstretch{2.5}


Addendum: If you prefer, a smaller \circ symbol you can use the option,

\scaleto{\circ}{2pt}%%%% <----- 2pt, or any value neq 0


\documentclass[a4paper,12pt]{article}
\usepackage{amssymb,mathtools}
\usepackage{accents}
\usepackage{scalerel}

\newcommand\arcsup[1]{\accentset{\overset{\scaleto{\circ}{2pt}}{\hstretch{1.8}{\frown}}}{#1}}
\begin{document}

$\bigl((\overline{M})_{\tau_1}\bigr)^{\!\mathsf{c}} = (\arcsup{M}^\mathsf{c})_{\tau_1}$
\end{document}


these are the screeshots for comparison:

\scaleto{\circ}{1.5pt}


Not exactly the answer to your question, but the package yhmath have the \widering command which can be useful to you:

\documentclass[twoside]{article}
\usepackage{fancyhdr}
\usepackage{nameref}
\usepackage{abraces}
\usepackage{amsfonts,amsmath, amssymb, mathtools}
\usepackage{yhmath}
\makeatletter
\newcommand*{\currentname}{\@currentlabelname}
\makeatother

\fancypagestyle{yourStyle}{
\fancyhf{}
}

\begin{document}

$$\left((\overline{M})_{\tau_1}\right)^\mathsf{c} = (\aoverbrace[L1R] {M^\mathsf{c}}^{\circ})_{\tau_1}$$
$$\left((\overline{M})_{\tau_2}\right)^\mathsf{c} = (\aoverbrace[L1R] {M^\mathsf{c}}^{\circ})_{\tau_2}$$

$$\left((\overline{M})_{\tau_1}\right)^\mathsf{c} = (\widering{M^\mathsf{c}})_{\tau_1}$$
$$\left((\overline{M})_{\tau_2}\right)^\mathsf{c} = (\widering{M^\mathsf{c}})_{\tau_2}$$

\end{document}


In the recent version 1.18 of newtxmath there are new math accents and macros. The macro \widering, as written into the guide, places a ring centered over an \overgroup, not dissimilar from its use in yhmath. But for my tastes the command \widering given by newtxmath have a better arc:

\documentclass[a4paper,12pt]{article}
\usepackage{newtxmath,newtxtext}

\begin{document}
$\bigl((\overline{M})_{\tau_1}\bigr)^{\!\mathsf{c}} = (\widering{M}{}^{\mathsf{c}})_{\tau_1}$
\end{document}


See this output:

Or changed the position of superscript:

\documentclass[a4paper,12pt]{article}

\usepackage{newtxmath,newtxtext}

\begin{document}
$\bigl((\overline{M})_{\tau_1}\bigr)^{\!\mathsf{c}} = (\widering{M^{\mathsf{c}}})_{\tau_1}$
\end{document}