[Tex/LaTex] Vertical spacing before and after equation environment: empty line or not

amsmathcommentsequationsspacingtypography

The vertical spacing in front of and behind the amsmath equation environment is different whether I insert a blank line or not (im using KOMA-Script with parskip=half if this is important). I'd like to insert a blank line so that my code is more readable, but then the vertical space is rather big:

Some text here

\begin{equation}
  a = b
\end{equation}

Some other text

Way two (no blank line)

Some text here
\begin{equation}
  a = b
\end{equation}
Some other text

Way three (blank line only at the bottom, this looks very good, IMHO, but I think the spacing is asymmetric then):

Some text here
\begin{equation}
  a = b
\end{equation}

Some other text

I know I could fix the code readbility with commenting the blank lines

Some text here
%
\begin{equation}
  a = b
\end{equation}
%
Some other text

But my question is: Are there some typographical (thumb) rules, guidelines, do's or dont's or whatever, on how to space the equation environment?

Best Answer

Your method (1) is simply wrong: a displayed equation should never start a paragraph.

If it ends a paragraph, leave a blank line after it (case 3); if the paragraphs continues, no blank line (case 2).

Setting a nonzero parskip does not increase readability, in my opinion (which I share with people like Tschichold): it just puts big white stripes on the page, spoiling its uniform grey color.

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