Too many blanks between summation symbol and its associated expression

I am actually new to latex, so this is very basic and ridiculous question. However, I cannot eliminate the blank between f(e) and the summation symbol. Besides, the equal sign is so far from the summation symbol. How can I solve these ?

Latex Code:

\sum_{e \, into \, node \, v} f(e) = \sum_{e \, out \, of \, node \, v} f(e)


• You are welcome to TeX.SE. For my opinion it is all to remake the code. What is your complete code where the preamble is? What packages do you use, etc. Commented May 30, 2018 at 20:28
• You could try something like \sum_{\mathclap{\text{$e$ into node $v$}}} f(e) = \sum_{\mathclap{\text{$e$ into node $v$}}} f(e) with mathtools. But then you might end up with the text running into the summands or the equal sign. Edit OK, I just checked this and it looks absolutely terrible. Commented May 30, 2018 at 20:28
• never use math italic for words: e \, into \, node \, v the font is designed to make adjacent letters not look like a word but like a product of variables. Commented May 30, 2018 at 20:30
• As I write these latex codes in os-x application "pages", most of packages and math functions do not exist unfortunately. Commented May 30, 2018 at 20:39
• When using text I would vote for \textnormal rather than \text. Commented May 30, 2018 at 23:07

You can use \smashoperator from mathtools (I don't recommend it) or split the subscript across two lines. Or, probably better, use suitable notation.

\documentclass{article}
\usepackage{mathtools}

\begin{document}

$\smashoperator[r]{\sum_{\text{e into node v}}} f(e) = \smashoperator[r]{\sum_{\text{e out of node v}}} f(e)$

$\sum_{\substack{\text{e into}\\\text{node v}}} f(e) = \sum_{\substack{\text{e out of}\\\text{node v}}} f(e)$

$\sum_{e\in v^{\leftarrow}} f(e) = \sum_{e\in v^{\rightarrow}} f(e)$

\end{document}


• "+1" sure. :-) Best best answer. Commented May 30, 2018 at 21:04
• Is there any specific reason why you say smashoperator is not recommended?
Commented May 31, 2018 at 6:31
• @JAD I mean, look at the output! ;-) Commented May 31, 2018 at 6:46

I was elaborating over my idea about visual formatting, when @Sebastiano’s use of \substack suggested a better alternative…

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly
% declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
\usepackage[utf8]{inputenc}      % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{mathtools}

\begin{document}

Some text before the equation.
\begin{align}
\sum_{\mathclap{\text{$e$ into node $v$}}} f(e)
\mspace{9mu}&=\mspace{9mu}
\sum_{\mathclap{\text{$e$ out of node $v$}}} f(e)
\\medskipamount] \sum_{\mathclap{\substack{\text{e into}\\\text{node v}}}} f(e) &= \sum_{\mathclap{\substack{\text{e out of}\\\text{node v}}}} f(e) \end{align} Some text after the equation. \end{document}  The output: • I want upvoted all. +1 :-) Commented May 30, 2018 at 21:03 • This is what I was gonna do! +1 :) Commented May 30, 2018 at 21:04 • @Au101: Yes, it's pretty obvious… But the most comprehensive answer is—as (almost) always—egreg’s (indeed, \smashoperator is the way to go here!). – GuM Commented May 30, 2018 at 21:11 Here's a solution that uses the \smashoperator macro of the mathtools package. Note that there's now no gap between the summation symbols and f(e). However, there's still a gap between the = symbol and the second summation symbol, to keep the longish material below the summation symbols from getting entangled. \documentclass{article} \usepackage{mathtools} % for '\smashoperator' macro \begin{document} \[ \smashoperator{\sum_{\text{r into node v}}} f(e) = \smashoperator[r]{\sum_{\text{e out of node v}}} f(e)
\end{document}

• Sure that is the best. +1. Commented May 30, 2018 at 21:02

This could be one of many solutions but it is not the best.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\sum _{e \text{ into node }v} \hspace{-.5cm} f(e)=\sum _{e\,\, \text{out of node }v} \hspace{-.5cm} f(e)$

\end{document}