# No spacing after \Sigma?

There seems to be barely any spacing (if at all) after \Sigma, making it hard to read. Is this normal? Is there any way around it?

 $\Sigma_{v \in V} \alpha$


Output:

Desired output:

• Add your own horizontal space. See What commands are there for horizontal spacing? – Werner Dec 9 '18 at 17:07
• why don't you use \sum? – Ulrike Fischer Dec 9 '18 at 17:15
• \Sigma is a normal greek letter so has no spacing just as abc has no extra spacing, if you mean summation operator then use \sum which is a different character and also specified as a math operator so has different spacing. – David Carlisle Dec 9 '18 at 17:25
• – egreg Dec 9 '18 at 19:03
• there are spacing symbols defined. the one i use most is: \, but others exist as well ... – der bender Dec 9 '18 at 19:58

You should use \sum, not \Sigma, to create a summation symbol. The \sum symbol is slightly larger than \Sigma when used in text style, and a whole lot larger when used in display style. In addition, the math type of \sum is math-op ("math operator"), whereas the math type of \Sigma is math-ord ("ordinary atom"); this strongly affects the amount of whitespace TeX inserts before and after the symbol.

\documentclass{article}
\begin{document}
$\Sigma_{i\in V} \beta_i \quad \sum_{i\in V} \beta_i \quad \sum\limits_{i\in V}\beta_i \quad {\displaystyle\sum\nolimits_{i\in V} \beta_i} \quad \displaystyle\sum_{i\in V} \beta_i$
\end{document}