11

I have a question on how to have the following in an equation.

Here is some working code to start with:

\documentclass[12pt]{article}

\begin{document}

\begin{equation}
P(X)=\sum_{X\in A}\cdots \sum
\end{equation}

\end{document}

enter image description here

14

Use \underset from amsmath.

\documentclass[12pt]{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}
P(X)=\underset{X\in A}{\sum \cdots \sum}
\end{equation}

\end{document}

enter image description here

If this is a common occurrence in your document, you might consider creating it as a new operator with limits, which is discussed in How to create my own math operator with limits? and in percusse's answer to your question here.

|improve this answer|||||
16

Here is one way via declaring an operator

\documentclass[12pt]{article}
\usepackage{mathtools} %<-- loads, enhances amsmath
\DeclareMathOperator*{\manysum}{\sum\cdots\sum}

\begin{document}

\begin{equation}
P(X)=\manysum_{X\in A}(x_{ijklm})
\end{equation}
Also inline \(P(X)=\manysum_{X\in A}(x_{ijklm})\).
\end{document}

enter image description here

|improve this answer|||||
13

A more general answer:

\documentclass[12pt]{article}
\usepackage{amsmath}

\makeatletter
\newcommand{\Multi@Sum}[1]{%
  \ifcase#1\relax\or
    \or
    \sum\sum\or
    \sum\sum\sum\else
    \sum\dots\sum
  \fi
}
\newcommand\ssum{\DOTSB\mathop{\Multi@Sum{2}}\slimits@}
\newcommand\sssum{\DOTSB\mathop{\Multi@Sum{3}}\slimits@}
\newcommand\sdotssum{\DOTSB\mathop{\Multi@Sum{-1}}\slimits@}
\makeatother

\begin{document}

\begin{equation}
\sum_{x\in A}\quad
\ssum_{x\in A}\quad
\sssum_{x\in A}\quad
\sdotssum_{x\in A}
\end{equation}

\end{document}

enter image description here

This will respect the option nosumlimit or sumlimit (default) given to amsmath.

You may want to change the \sum\dots\sum line to

\sum\!\cdots\!\sum

getting, for \sdotssum_{x\in A} the output

enter image description here

|improve this answer|||||

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.