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

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 3

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

\documentclass{article}
\begin{document}
\[
  \sum_{i=1}^{10}{}^{'} f(x) 
  \mbox{\quad or \quad} 
  \sum_{i=1}^{10}{\vphantom{\sum}}' f(x)
\]
\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 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

Yes I agree with Ant and to give more information you can read Mathmode.pdf, the very fine document of Herbert Voss. You can read this document with the command texdoc mathmode.pdfin a terminal

About \sideset

This is a command for a very special purpose, to combine over/under limits with superscript/subscripts for the sum-symbol. For example: it is not possible to place the prime for the equation 35.4 near to the sum symbol, because it becomes an upper limit when writing without an preceeding {}.Now it is possible to write the equation \ref{eq:sideset} in a proper way with the command \verb|\sideset{}{'}| before the sum symbol:

\begin{equation}
   \sideset{}{'}\sum_{n<k\atop n\ \textrm{odd}}nE_{n}
\end{equation}

Answer 6

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