How to get slender \prod symbol in display mode

Question

When I use \prod in math display mode it comes in darker form. How can I make it slender?

\documentclass[11pt,reqno,fleqn,a4paper]{article}
\usepackage{amsmath,amssymb,amsfonts}
\begin{document}
The following has product symbol in bold form $$\prod_{i=1}^{n}\bigcup_{\alpha} A_{\alpha_i}$$
\end{document}

If \[ ... \] is used instead of $$ ... $$ for math display mode, I get the same result.

P.S. Here I said bold by the look of the font. I know there is a much darker version of this symbol in the bold symbol.

Answer 1

That's the standard shape of the symbol and you'll find thick side bars in most books.

However, you can use the “concrete“ version of the symbol.

\documentclass{article}

% redefine \prod prior to amsmath doing its job
\DeclareSymbolFont{slenderlargesymbols}{OMX}{ccex}{m}{n}
\DeclareMathSymbol{\prod}{\mathop}{slenderlargesymbols}{"51}

\usepackage{amsmath,amssymb,amsfonts}

\begin{document}

The following has a slender product symbol
\[
\prod_{i=1}^{n}\bigcup_{\alpha} A_{\alpha_i}
\]

\end{document}