[Tex/LaTex] Creating math symbol by stacking and superimposing symbols

math-modesymbols

I'd like to have the usual symbol for the infimal convolution. I've tried \stackrel{+}{\vee}, but it scales down the plus, which I don't want. I also tried \atop, but the symbol gets really big and ugly. I'd like something more like \pm… But unfortunately I'm having a hard time finding its code.

Best Answer

Infimal convolution symbols across the Internet vary, so this one is taken from Wikipedia:

enter image description here

\documentclass{article}
\usepackage{amsmath,amssymb}% http://ctan.org/pkg/{amsmath,amssymb}
\DeclareMathOperator{\iconv}{\mathbin{\star_{\text{inf}}}}%
\begin{document}
\[ (f\iconv g)(x) = \inf\{f(x-y)+g(y)\,\vert\,y\in\mathbb{R}^n\} \]
\end{document}

Here's another one taken from this source:

enter image description here

\documentclass{article}
\usepackage{amsmath,amssymb}% http://ctan.org/pkg/{amsmath,amssymb}
\usepackage{graphicx}% http://ctan.org/pkg/graphicx
\DeclareMathOperator{\iconv}{%
  \mathbin{\ooalign{\raisebox{-.5ex}{$\vee$}\cr\hidewidth\raisebox{.5ex}{\scalebox{.7}{+}}\hidewidth}}}%
\begin{document}
\[ (f\iconv g)(x) = \inf\{f(x-y)+g(y)\,\vert\,y\in\mathbb{R}^n\} \]
\end{document}

Or, create it yourself (from the above, and therefore does not require graphicx):

enter image description here

\documentclass{article}
\usepackage{amsmath,amssymb}% http://ctan.org/pkg/{amsmath,amssymb}
\DeclareMathOperator{\iconv}{%
  \mathbin{\ooalign{\raisebox{-.5ex}{$\triangledown$}\cr\hidewidth\rule[.3ex]{.4pt}{1ex}\hidewidth}}}%
\begin{document}
\[ (f\iconv g)(x) = \inf\{f(x-y)+g(y)\,\vert\,y\in\mathbb{R}^n\} \]
\end{document}

If you're going to use these symbols in super-/subscripts, then more works needs to be done. The use of \ooalign for symbol construction is discussed in \subseteq + \circ as a single symbol (“open subset”).