# Vertical space before and after equations

The vertical space before and after equation (1) is greater than the vertical space before and after equation (2).

Which is the rule/reason for that?

\documentclass{book}
\usepackage{amsmath,amsfonts}
\usepackage{setspace}
\usepackage{mwe}
\begin{document}
\doublespacing
Is it normal that the vertical space before and after this equation:
$$a = b + c$$
is more than the space before and after this other equation?
$$d=\sum_{i=1}^{k}e_i$$
\blindtext
\end{document}


• Yes, it is normal. Measure the distance between the baselines. Aug 14, 2019 at 22:00
• The spaces are exactly the same -- compare the gaps between the surrounding text, not the distance from the highest/lowest elements of the displayed material. The difference you observe is the fact that there is a large operator with limits in the second display; that is not part of the defined measurement, which is correctly described by @egreg. Aug 14, 2019 at 22:22
• use \vspace before and after the equation like \vspace{-.5cm} May 15, 2020 at 18:31
• @Jarod_83 -- This is almost never a good idea. Using an explicit \vspace, even negative, before a display makes it possible for the page to break there, a condition that is ordinarily prohibited. May 16, 2020 at 0:58