+def
+\backslash
+clap#1{
+\backslash
+hbox to 0pt{
+\backslash
+hss #1
+\backslash
+hss}}
+\begin_inset Newline newline
+\end_inset
+
+
+\backslash
+def
+\backslash
+mathclap {
+\backslash
+mathpalette
+\backslash
+mathclapinternal}
+\begin_inset Newline newline
+\end_inset
+
+
+\backslash
+def
+\backslash
+mathclapinternal #1#2{
+\backslash
+clap{$
+\backslash
+mathsurround =0pt #1{#2}$}}
+\end_layout
+
+\begin_layout Standard
+This defines the command
+\series bold
+
+\backslash
+mathclap
+\series default
+
+\begin_inset Index idx
+status collapsed
+
+\begin_layout Plain Layout
+Commands ! M !
+\backslash
+mathclap
+\end_layout
+
+\end_inset
+
+ that sets the width of the limit to 0
+\begin_inset space \thinspace{}
+\end_inset
+
+pt.
+ The command scheme is
+\end_layout
+
+\begin_layout Standard
+
+\series bold
+
+\backslash
+mathclap{limit}
+\end_layout
+
+\begin_layout Standard
+where the limit can consist of several conditions.
+\end_layout
+
+\begin_layout Standard
+Applied on formula
+\begin_inset CommandInset ref
+LatexCommand eqref
+reference "eq:substack"
+
+\end_inset
+
+, one uses the command
+\end_layout
+
+\begin_layout Standard
+
+\series bold
+
+\backslash
+sum_
+\backslash
+mathclap{
+\backslash
+substack
+\begin_inset ERT
+status collapsed
+
+\begin_layout Plain Layout
+
+
+\backslash
+spce
+\end_layout
+
+\end_inset
+
+0<k<1000 Ctrl+Return
+\end_layout
+
+\begin_layout Standard
+to create the lower limit.
+ The summand is now directly behind the summation operator:
+\begin_inset Formula
+\[
+\sum_{\mathclap{\substack{0<k<1000\\
+\\
+k\,\in\,\mathbb{N}
+}
+}}^{n}k^{-2}
+\]
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+\begin_inset VSpace bigskip
+\end_inset
+
+How to use one limit for several operators is described in
+\begin_inset CommandInset ref
+LatexCommand ref
+reference "sub:Self-defined-Operators"
+
+\end_inset
+
+.
+\end_layout
+
+\begin_layout Subsection
+Decoration for Operators
+\begin_inset Index idx
+status collapsed
+
+\begin_layout Plain Layout
+Operators ! Decoration
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+With the commands
+\series bold
+
+\backslash
+overset
+\series default
+
+\begin_inset Index idx
+status collapsed
+
+\begin_layout Plain Layout
+Commands ! O !
+\backslash
+overset
+\end_layout
+
+\end_inset
+
+ and
+\series bold
+
+\backslash
+underset
+\series default
+
+\begin_inset Index idx
+status collapsed
+
+\begin_layout Plain Layout
+Commands ! U !
+\backslash
+underset
+\end_layout
+
+\end_inset
+
+ characters can be placed above or below an operator, respectively.
+ With the command
+\series bold
+
+\backslash
+sideset
+\series default
+
+\begin_inset Index idx
+status collapsed
+
+\begin_layout Plain Layout
+Commands ! S !
+\backslash
+sideset
+\end_layout
+
+\end_inset
+
+ characters can be set before and behind a big operator.
+ The command scheme is:
+\end_layout
+
+\begin_layout Standard
+
+\series bold
+
+\backslash
+sideset{character
+\series default
+
+\series bold
+before}{character
+\series default
+
+\series bold
+behind}
+\end_layout
+
+\begin_layout Standard
+
+\series bold
+
+\backslash
+sideset
+\series default
+ must always be before the operator.
+ You can decorate with several characters and even with other operators
+ and symbols.
+ To place for example only characters behind a big operator, write nothing
+ between the first braces but don't omit the braces.
+\end_layout