Some definitions of interest.
int_seg	Def  {i..j} == {k:| i  k < j }
	Thm*  m,n:. {m..n}  Type
int_upper	Def  {i...} == {j:| ij }
	Thm*  n:. {n...}  Type
nat	Def   == {i:| 0i }
	Thm*    Type
le	Def  AB == B<A
	Thm*  i,j:. (ij)  Prop

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