I've tried reading various sources (in particular Tex By Topic; I don't have a copy of the TeXBook) and experimenting on my own, but I'm still unclear as to how exactly the line spacing in and around a multiline math environment is determined by the parameters
Can someone explain exactly how the skips are computed? (Ideally it should include a description of what happens if one or more of these parameters is made negative.)
I'm especially interested in
\lineskiplimit, since I've seen some strange results from playing with these.
For a MWE, see the example given in Set a minimum space above and below displayed math