Some definitions of interest.
int_nzero	Def  == {i:| i  0 }
	Thm*   Type
nat	Def  == {i:| 0i }
	Thm*   Type
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