Some definitions of interest.
divides	Def b | a == c:. a = bc
	Thm* a,b:. (a | b)  Prop
nat	Def  == {i:| 0i }
	Thm*   Type
pm_equal	Def i =  j == i = j    i = -j
	Thm* a,b:. a =  b  Prop

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