# A symbol above a comma

How can I put a symbol above a comma? For example in

• – Werner Apr 9 '15 at 19:25

You can use \overset from amsmath:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$\{L(\lambda)\ \overset{\otimes}{,}\ L(\mu)\}$
\end{document}


I added optional spaces to make it look more like your example:

As noted in the comment, you can use \scriptscriptstyle to make \otimes smaller:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$\{L(\lambda)\ \overset{\scriptscriptstyle\otimes}{,}\ L(\mu)\}$
\end{document}


• You shouldn’t use spaces like that, but wrap the symbol in \mathbin or \mathpunct depending on the desired interpretation to get proper spacing. – Emil Jeřábek Apr 10 '15 at 12:55

The following example sets \otimes as upper limit over the comma, which is turned to a math operator via \mathop. This also decreases the size of ⊗. By explicitly using \scriptscriptstyle, the symbol can be decreased further, see Manuel's comment. Then the result is wrapped in \mathpunct to keep the property of the comma as punctuation character:

\documentclass{article}

\newcommand*{\commaotimes}{%
\mathpunct{%
\mathop{,}\limits^{\otimes}%
}%
}
\newcommand*{\commaotimessmall}{%
\mathpunct{%
\mathop{,}\limits^{\scriptscriptstyle\otimes}%
}%
}

\begin{document}
$\{ L(\lambda) \commaotimes L(\mu) \}$
$\{ L(\lambda) \commaotimessmall L(\mu) \}$
\end{document}


Remark:

• The symbol \commatimessmall works well in math styles \displaystyle and \textstyle. For \scriptstyle and \scriptscriptstyle the symbol \otimes does not change it size, because there is no \scriptscriptscriptstyle.
• I think it' \scripscriptstyle (which also looks better, in my opinion). – Manuel Apr 9 '15 at 19:43
• keeping the \mathpunct property leaves more space after the compound than before. is that desired? – barbara beeton Apr 9 '15 at 20:14
• @barbarabeeton I have understood the symbol from the question as annotated comma. Therefore I have added \mathpunct to the the normal spacing of a comma with more space after the symbol. But \mathpunct can be easily replaced by \mathbin or \mathrel to change the spacing behavior of the symbol. – Heiko Oberdiek Apr 9 '15 at 20:22

One possibility \stackrel{\otimes}{,}:

$\left\{L\left(\lambda\right)\ \stackrel{\otimes}{,}\ L\left(\mu\right)\right\}$


• Perhaps you should use a \raisebox – user31729 Apr 9 '15 at 19:21