Some definitions of interest.
divides	Def  b | a == c:. a = bc
	Thm*  a,b:. (a | b)  Prop
eval_factorization	Def  {a..b}(f) ==  i:{a..b}. if(i)
	Thm*  a,b:, f:({a..b}). {a..b}(f)
int_seg	Def  {i..j} == {k:| i  k < j }
	Thm*  m,n:. {m..n}  Type
nat	Def   == {i:| 0i }
	Thm*    Type

About: IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html