# How do I get a slanted \sum symbol?

I want to use a slanted \sum symbol denoting a different meaning from summation. How do I get a slanted \sum symbol?

• What is the intended meaning? Please reconsider this as the use of 2 very similar symbols, only distinguished by the fact that one is slanted, will be extremely confusing, as well as typographically bad. In mathematical typesetting, things of the same kind get typeset in similar ways e.g. all functions, all operators, all variables... in upright, in italic, in ... – cfr Jan 3 '15 at 2:45
• Can you draw what you're looking for? If it's a simple rotation, then the linked answers your question. If it's truly 'oblique', then perhaps not. – Sean Allred Jan 3 '15 at 4:27
• @cfr This is not duplicate, because rotating isn't slanting. – wipet Jan 3 '15 at 7:54

If you are using pdfTeX then you can try this code:

\def\itsum{\mathop{\mathpalette\itsumA{}\phantom\sum}}
\def\itsumA#1#2{\pdfsave\pdfliteral{1 0 .2 1 0 0 cm}\rlap{$#1\sum$}\pdfrestore}

$\sum_i^5 \itsum_j^{\,7} a_{ij}$


• Also works with LuaTeX 'out of the box' (those primitives are carried forward as-is) – Joseph Wright Jan 3 '15 at 14:23
• @JosephWright Of course. I "assume" :-) that LuaTeX users know that pdfTeX is included here. – wipet Jan 3 '15 at 14:26
• Actually you can generalize it with something like {if pdf}{<\pdfliteral code>}{<\special code>} – percusse Jan 4 '15 at 3:37
• @percusse I do something similar in my macros. If \pdfliteral isn't accessible then I define it as \def\pdfliteral#1{\special{pdf:literal #1}}. This allows me to keep the \pdfliteral-dependent macros unchanged. – wipet Jan 4 '15 at 6:58

One way to do it is to use a slanted capital sigma. By using the scalerel package, one can make that symbol (approximately) the same size as the original \sum operator:

\documentclass{article}
\usepackage{amsmath}
\usepackage{scalerel}
\DeclareMathOperator*{\itsum}{\scalerel*{\mathit{\Sigma}}{\sum}}
\begin{document}
$\sum_i x_i\quad\itsum_i x_i$
\end{document}


• Why did you make the slanted version larger? – cfr Jan 3 '15 at 3:25
• @cfr The reason the slanted one is larger can be determined by executing \fboxsep=0pt\fbox{$\mathit{\Sigma}$}\fbox{$\displaystyle\sum$} (with the scalerel package loaded). The \sum has a built in padding above and below the glyph, which is absent in the \Sigma (\mathit or otherwise). Thus, the \scalreled \Sigma is grown to the size of the padded \sum, which is slightly larger than the actual glyph. – Steven B. Segletes Jan 3 '15 at 4:20