This is not a math question as much as a process question. For the first time in my (very short) career, I find myself doing one of those messy calculations, where each 'line' of the calculation can spread over a page or three. Essentially all of the calculation is trivial if I'm willing to write some reasonable inequalities in places, and all of these choices are obvious as they're being made, but I am having a rough time keeping the assumptions on term sign required for the various inequalities and the calculations themselves even close to organized, and the copying errors are a nightmare.


Does anybody have any good suggestions on how to stay organized for this sort of trivial-in-theory but messy-in-practice calculation? What do you actually *do* in these situations? This is especially directed at people in areas like statistical physics or mathematical statistics where these sorts of things show up frequently, and there must be some way of dealing with them. Clever renaming of variables, latexing as you go, good use of Maple...?



Medium-Sized Calculations and Organization
Mathematica can be very useful for this kind of thing. If you're good enough at it you can force it to go through calculations pretty much step-by-step if you need it too. You can also export its output to LaTeX, which is very nice and saved me a lot of work on various physics homeworks! 


For more complicated things, you can often still make mathematica do it, but it's often better (and can be more insightful) to try to restructure things into smaller blocks that are easier to handle. You can do this through renaming things, or lemmas, or whatever else. In physics, physical intuition about things like conserved or almost conserved quantities can be really useful to use here, since they can tell you about things you might otherwise miss.


