Some definitions of interest.
label	Def t  ...$L == t
nat	Def  == {i:| 0i }
	Thm*   Type
	Thm*   S
le	Def AB == B<A
	Thm* i,j:. (ij)  Prop
not	Def A == A  False
	Thm* A:Prop. (A)  Prop

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