Some definitions of interest.
nequal	Def a  b  T == a = b  T
	Thm* A:Type, x,y:A. (x  y)  Prop
sfa_doc_sample_intmod	Def  mod k == x,y://(m:. x-y = mk)
	Thm* k:.  mod k  Type

About: IF YOU CAN SEE THIS go to http://www.cs.cornell.edu/Info/People/sfa/Nuprl/Shared/Xindentation_hack_doc.html