LaTeX puts too much space next to integrals

Question

Integrals with limits take up width horizontally that includes their limits. In other words, if you have an integral with large limits below (or above) the integral

\int\limits_{-\infty < x < c} (c - x) \ dP(x)

you are left with a large amount of space to the left and right of the integral before the integrand (c - x) starts. This is sometimes desirable, but in my case it isn't, since I have a whole bunch of integrals like this all in the same expression. Is there a way to make whatever is inside the integral snuggle up next to the integral sign, ignoring the width of the limit?

Answer 1

Something like this will do the trick.

\usepackage{amsmath}
\def\mathclap#1{\text{\hbox to 0pt{\hss$\mathsurround=0pt#1$\hss}}}
\begin{document}
\[
\int\limits_{\mathclap{-\infty < x < c}} (c - x) \ dP(x)
\]
\end{document}

More about such tricks is given in this article.

Answer 2

The mathtools package contains a definition for \mathclap, and also a command \smashoperator that is a bit more convenient:

\smashoperator{\int_{\infty < x < c}} (c - x) \, dP(x)