[Tex/LaTex] Filled \Diamond-product sign

Question

I use the multiple \Diamond-product sign (\bDiamond) as described in sign for multiple $\Diamond$-product. Now, in addition, I would like to have a filled \Diamond-product sign, i.e. filled with black. Any suggestions?

Answer 1

With amssymb you have \blacklozenge:

\documentclass{article}
\usepackage{amssymb,graphicx}

\newcommand{\bDiamond}{\mathbin{\Diamond}}
\newcommand{\bLozenge}{\mathbin{\blacklozenge}}

\makeatletter
\newcommand\bigDiamond{\mathop{\mathpalette\bigDi@mond\relax}}
\newcommand\bigDi@mond[2]{%
  \vcenter{\hbox{\m@th
    \scalebox{\ifx#1\displaystyle 2\else1.2\fi}{$#1\Diamond$}%
  }}%
}
\newcommand\bigLozenge{\mathop{\mathpalette\bigL@zenge\relax}}
\newcommand\bigL@zenge[2]{%
  \vcenter{\hbox{\m@th
    \scalebox{\ifx#1\displaystyle 2\else1.2\fi}{$#1\blacklozenge$}%
  }}%
}
\makeatother

\begin{document}
\[
\bigoplus_{i=1}^n % just for comparison
\bigDiamond_{i=1}^n (a_i\bDiamond b_i)\quad
\textstyle\bigDiamond_{i=1}^n a_i\quad
\scriptstyle\bigDiamond_{i=1}^n a_i\quad
\scriptscriptstyle\bigDiamond_{i=1}^n a_i
\]
\[
\bigoplus_{i=1}^n % just for comparison
\bigLozenge_{i=1}^n (a_i\bLozenge b_i)\quad
\textstyle\bigLozenge_{i=1}^n a_i\quad
\scriptstyle\bigLozenge_{i=1}^n a_i\quad
\scriptscriptstyle\bigLozenge_{i=1}^n a_i
\]
\end{document}