What is the difference between these two?
http://en.wikibooks.org/wiki/TeX/abovedisplayskip
http://en.wikibooks.org/wiki/TeX/abovedisplayshortskip
I don't know why, but it seems to work unusually.
\setlength{\abovedisplayskip}{5pt}
\setlength{\belowdisplayskip}{50pt}
\setlength{\abovedisplayshortskip}{2pt}
\setlength{\belowdisplayshortskip}{2pt}
\begin{equation}
u_{i,t} = u_{i,t-1} + v_t
\end{equation}
\begin{equation}
u_{i,t-1} = u_{i,t-2} + v_{t-1}
\end{equation}
\begin{equation}
\Delta u_{it} = u_{i,t} - u_{i,t-1} = u_{i,t-1} + v_t - u_{i,t-1} =
v_t
\end{equation}
So why does it look like this:
I expected the short display skip to be between consecutive formulae and the regular skip to be before and after the first and last in the series, or something like that. In any case, why the heck would it do this?