# How to create symbol “cross product with dot under it”

Is there any package with that symbol circled in orange in the photo? Thanks for answering.

• What does this symbol mean? If it's that rare that Tex doesn't have it, it means Knuth never used it, so the rest of us don't know what it means either. Why do you want to use it? – D Duck Nov 17 '18 at 11:35
• @DDuck That book is written in Tex so it must exist. We are using that symbol for Cartesian product of two semialgebras. – Peđa Pilipović Nov 18 '18 at 19:53
• Did you look in tug.ctan.org/info/symbols/comprehensive/symbols-a4.pdf ? – D Duck Nov 18 '18 at 20:09

Using \ooalign (one of my favorite toys) together with \mathpalette for properly scaling the symbol if in subscripts or superscripts. Note that the dot is properly centered, contrary to what the image shows.

\documentclass{article}
\usepackage{amsmath}

\makeatletter
\newcommand{\timesdot}{\mathbin{\mathpalette\timesdot@\relax}}
\newcommand{\timesdot@}[2]{%
\ooalign{$\m@th#1\times$\cr\hidewidth$\m@th#1.$\hidewidth\cr}%
}
\makeatother

\begin{document}

$\mathcal{I}\timesdot\mathcal{J}$

\end{document}


With stackengine:

\documentclass{article}
\usepackage{amsfonts}
\usepackage{stackengine}
\newcommand\timesdot{\stackMath\mathbin{\stackinset{c}{0ex}{c}{-0.49ex}{\scriptscriptstyle.}{\times}}}

\begin{document}

$\mathcal I \timesdot \mathcal J$

\end{document}


If larger space is also OK:

\documentclass{article}

\usepackage{graphicx}
\usepackage{mathabx}

\begin{document}

\rotatebox{180}{$\dottimes$}

\end{document}


• Observe that the dot is not inside the times. – Sigur Nov 16 '18 at 23:14
• @Sigur Sure, that's why I make the if case for larger space – daniel Nov 16 '18 at 23:40
• Also, try to insert those 2 letters around it, as OP had shown. – Sigur Nov 16 '18 at 23:44