# Changing the kpfonts \sum symbol

I like the kpfonts package. It's a nice font and some of the extra symbols it defines are sometimes useful. But I do not like the \sum symbol either in displaystyle or inline. It's too thin and too tall. I tried looking at how kpfonts defines \sum in the hope of just being able to \renewcommand but it does something weird with the maths operators, in order to have package options like fullsumlimits.

How can I get the \sum symbol looking more like the cm sum, for example, without breaking kpfonts package options?

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Have a look at the answers to this question.

\DeclareSymbolFont{cmlargesymbols}{OMX}{cmex}{m}{n}
\let\sumop\relax
\DeclareMathSymbol{\sumop}{\mathop}{cmlargesymbols}{"50}


That gets you the \sum from Computer Modern but called \sumop. With kpfonts loaded, that should make the macro \sum respect the various limits option while using the CM sum symbol.

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This fix works, but it breaks the fullsumlimits option in kpfonts. kpfonts has a weird way of defining the operators that involves an extra command. –  Seamus Sep 12 '10 at 15:42
@Seamus: I believe that edit should address your comment. –  TH. Sep 13 '10 at 5:06
The middle line should be \let\sumop\relax otherwise all the sums just disappear! –  Seamus Sep 13 '10 at 11:18
Good catch. I've fixed the answer. –  TH. Sep 13 '10 at 17:07
@TH. how can i replace all math symbols with the exception for the normal letters a,b,c... and the \hbar command from computer modern or the mathdesign package ? and how i can know if this substitution is typographically correct? –  FormlessCloud Aug 10 '12 at 14:23