# Symbol: Put a smile symbol under a plus

I would like to have a \smile symbol under a plus symbol. What I have so far is

\newcommand{\pluss}{\raisebox{-.5ex}{\,$\overset{\textstyle{\raisebox{-0.5ex}{$+$}}}{\smile}$}\,}


However, I would like to have the plus further below. I tried to do this via the \raisebox command (as you can see). This works to some extend, but when I go further than -0.5ex, the whole thing will go down instead of just the plus symbol.

• In which context should it be used? – Bernard Aug 13 at 18:24
• @Bernard Why is this relevant? I don't understand these kind of questions.... – amsmath Aug 13 at 18:30
• I mean – will it be specifically used in mathmode, or is it just some kind of smiley? – Bernard Aug 13 at 18:34
• @Bernard Oh, I'm sorry. Yes, only in math mode. It's supposed to be a special symbol for an operator sum. I got now a quick and dirty solution, but I don't think LaTeX enthusiasts would like it: \newcommand{\pluss}{\,\text{\raisebox{-.4ex}{$\smile$}}\text{\hspace{-1.3ex}\raisebox{.4ex}{$+$}}\,} – amsmath Aug 13 at 18:37
• @amsmath Great! In TeX, \mathbin and \mathrel have slightly different spacing. So, when I say binary or relational in this context, I’m referring to the TeX character class—you’re certainly correct that, mathematically, relational operators are binary! If you like how the answers look, you don’t need to modify them. In other cases, you might want to wrap the symbols you generate in something like \mathrel{\SomeRelationalSymbol}. – Davislor Aug 14 at 15:42

With some low level TeX programming:

\documentclass{article}
\usepackage{amsmath}

\makeatletter
\DeclareRobustCommand{\pluss}{\mathbin{\text{\pluss@}}}
\newcommand{\pluss@}{%
\vtop{%
\offinterlineskip\m@th
\halign{\hfil##\hfil\cr$+$\cr$\smile$\cr}%
}%
}
\makeatother

\begin{document}

$3\pluss 4+5$

$\scriptstyle 3\pluss 4+5$

\end{document}


With a smaller \smile:

\documentclass{article}
\usepackage{amsmath}

\makeatletter
\DeclareRobustCommand{\pluss}{\mathbin{\text{\pluss@}}}
\newcommand{\pluss@}{%
\vtop{%
\offinterlineskip\m@th
\halign{\hfil##\hfil\cr$+$\cr$\scriptstyle\smile$\cr}%
}%
}
\makeatother

\begin{document}

$3\pluss 4+5$

$\scriptstyle 3\pluss 4+5$

\end{document}


• I checked this answer because it doesn't require additional packages. – amsmath Aug 14 at 11:32

Here is an easy solution (I think) with stackengine:

\documentclass{article}
\usepackage{stackengine}
\newcommand\pluss{\mathop{\stackMath\stackinset{c}{0pt}{c}{-1ex}{{\smile}}{{+}}}}

\begin{document}

$\pluss_{k} f(k)$

\end{document}


I'm not sure exactly what spacing you want, so this is an adjustable approach using xparse around your original design.

\documentclass[11pt]{article}

\usepackage{amsmath,xparse}

\NewDocumentCommand{\pluss}{O{-.5ex} O{0.5ex}}{%
\raisebox{#1}{\,$\overset{\textstyle{\raisebox{#2}{$+$}}}{\smash{\smile}}$}\,%
}

\begin{document}

$3 \pluss 4$

$3 \pluss[0.ex][0.2ex] 4$

$3 \pluss[-0.3ex][0.2ex] 4$

\end{document}


You can adjust it until you find the defaults you like.