[ho-tex] vertical spacing with amsmath+fleqn+hyperref

[David Carlisle]

On 17 May 2016 at 00:02, Reinhard Kotucha <reinhard.kotucha at web.de> wrote:
> On 2016-05-16 at 23:19:23 +0100, David Carlisle wrote:
>
>  > see
>  > http://tex.stackexchange.com/questions/309096/inconsistent-vertical-space-after-first-beginequation/309099#comment750929_309099
>  >
>  > for discussion of related issues
>
> There you say
>
>    Never leave a blank line before a displayed equation, or use two
>    consecutive equations. Use an environment for a multiline display
>    such as align or multline from amsmath –
>
> I disagree.  Paragraphs denote the logical structure of a document and
> it should be possible to insert these blank lines whenever
> appropriate.  If this isn't supported by LaTeX, it's a severe bug.
>
> Regards,
>   Reinhard
>
It's a feature of tex-the-program and pretty hard to work round,
starting a paragraph with display math simply is not possible in tex.
If you have a blank line before display math tex starts a paragraph
that just has indentation box and parfillskip glue then following that
white line has the abovedisplayshortskip, so the end result looks like
vertical space but most of it it isn't dropped at a page break as it
is an empty line of a paragraph not vertical space.

Not putting a blank line before a display is the only real alternative
on plain or latex any system that tried to work round this would b
emassively incompatible with existing documents.

David