6:16 AM
> For conditions in set notation, use again \mid.
I wonder whether we should mention also adjusting vertical height using \left..\middle..\right there.
But that is probably too fancy (and unnecessary for Math.SE - which is not a professional publication).
And also it is likely a bit complicate for beginners.
This is mentioned in some TeX.SE threads.
What I mean is this. I can use \left, \right with curly brackets.
$\left\{n \mid \frac{A(n)}n\le\varepsilon\right\}$
Some people might prefer to increase also the size of "|", but in that case \mid can no longer be used (at least without some modification).
$\left\{n \middle| \frac{A(n)}n\le\varepsilon\right\}$
However, spacing is not right, so I might need to adjust it:
$\left\{n \,\middle|\, \frac{A(n)}n\le\varepsilon\right\}$ or $\left\{n \;\middle|\; \frac{A(n)}n\le\varepsilon\right\}$
This is probably not needed in that post, still I've at least ask here.
(Although perhaps I would include some example in the bullet point about set notation.)
Personally, when I LaTeX documents, I use ";" rather than "|" - but that is just my personal preference.
