Using a single symbol from kpfonts

Question

I would need some help by extracting the "\varprod"-symbol from the kpfonts package. Similar to how it is done here for the subset-symbol of the mathabx package. Although there is a description how to do it, I can't get my head around the code. Help would be appreciated a lot.

Thanks in advance

Answer 1

You have to do some chasing in kpfonts.sty to arrive at

\documentclass{article}

\DeclareSymbolFont{largesymbolsA}{U}{jkpexa}{m}{n}
\SetSymbolFont{largesymbolsA}{bold}{U}{jkpexa}{bx}{n}
\DeclareMathSymbol{\varprod}{\mathop}{largesymbolsA}{16}

\begin{document}
\[
\varprod_{i=1}^n A_i\ne\prod_{i=1}^n A_i
\]
\end{document}

The steps

1. Look for \varprod in kpfonts.sty; this shows the third code line above

   \re@DeclareMathSymbol{\varprod}{\mathop}{largesymbolsA}{16}
   

   (the re@ part must be removed)

2. Look for the definition of largesymbolsA which leads to the other two lines of code

   \DeclareSymbolFont{largesymbolsA}{U}{jkp\kp@famillem exa}{m}{n}
   \SetSymbolFont{largesymbolsA}{bold}{U}{jkp\kp@famillem exa}{bx}{n}
   

3. Finding what \kp@famillem means, but it's used for supplying an l if the light fonts are requested, otherwise it does nothing.

   \ifkp@lightmath
     \def\kp@famillem{l}
   \else
     \def\kp@famillem{}
   \fi
   

4. Test.

5. Hurray!