I need to smash a sum because its indices take too much vertical space. But then, it also change the horizontal spacing before it, as shown with the following MWE :
\documentclass[11pt,letterpaper,twoside]{book}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[total={6in,10in},left=1.5in,top=0.5in,includehead,includefoot]{geometry}
\usepackage{microtype}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools}
\begin{document}
Blablabla blabla bla bla:
\begin{equation}
x = \frac{1}{2} \sum_{n=1}^N x = \frac{1}{2} \smash{\sum_{n=1}^N x}.
\end{equation}
Blablabla bla bla blabla blaaaa.
\end{document}
How can I smash the sum without changing the horizontal spacings around it?
(* The small red cow in the picture is a signature to this very nice piece of primitive art. The picture is copyrighted and could be sold to MOMA!)
\mathop{\smash{...}}
{\sum}
will get different spacing to\sum
\smash
...the issue is the braces.