How to type primed sum?

Question

I need to type a "primed sum" (a summation symbol with a ' at the top right corner of the summation symbol) in latex. How can I do this?

Answer 1

The amsmath package has documentation which suggests there are 2 choices, depending on whether your sum has limits or not.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[\sum\nolimits'\] %if no limits in the sum
\[ \sideset{}{'}\sum_{n<k,\;\text{$n$ odd}} nE_n \] %if limits in the sum
$\sum^{'}$
\end{document}

Answer 2

I would suggest typesetting the summation (together with its limits) first, and then add the prime:

\documentclass{article}
\begin{document}
\[
  \sum_{i=1}^{10}{}^{'}f(x)
\]
\end{document}​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

If the summation limits are too wide, this may cause the prime to shift away (further to the right). However, some use of \mathclap (from the mathtools package) would be able to clear this problem. You didn't mention it, so I didn't include it here. Just know that it is possible.

Answer 3

The amsmath manual (p. 15) recommends using sideset:

\usepackage{amsmath}
\sideset{}{'}\sum_{\text{whatever}} x

(This works when there are limits to the sum, unlike, er, \nolimits.)

Answer 4

If you are using in text formulas, this works:

$\sum^{'}$

otherwise, to have the best of both worlds (something under or over sum symbol and prime) in display mode you can write:

\begin{equation}
\sum^{\infty}_{i=1}\phantom{}^{'}
\end{equation}

Answer 5

Use \nolimits to force the prime to the right of the summation: \sum\nolimits', to use it as a symbol of its own, you have to wrap it inside \mathord{}:

\def\xsum{\mathop{\sum\nolimits'}}
\[
\sum^{a+b}_{x+y=c}
\xsum^{a+b}_{x+y=c}
\]