# [texhax] Question about Small \sum

Tue Feb 14 18:36:26 CET 2006

On Tue, 14 Feb 2006, Oleg Katsitadze wrote:

> On Tue, Feb 14, 2006 at 10:32:44PM +0800, Leung Ngai-Hang Zachary wrote:
>> I'm wondering if there's a better way to make the \sum symbol small---after
>> all \textstyle affects the entire $...$ section, and I may just want
>> to change that symbol.
>
> You might like this approach:
>
> \def\textsum{\mathop{\textstyle\sum}\limits}
>
> $\textsum_{i=0}^n a_i$\quad $\sum_{i=0}^n a_i$.
> $$\textsum_{i=0}^n a_i \qquad \sum_{i=0}^n a_i.$$

You  can also try \medop from nccmath.sty.

\usepackage{nccmath}

$\medop\sum_{i=0}^n a_i$

The size is in between textstyle and displaystyle and looks better IMO.