Some definitions of interest.
eq_int	Def  i=j == if i=j true ; false fi
	Thm*  i,j:. (i=j)
int_seg	Def  {i..j} == {k:| i  k < j }
	Thm*  m,n:. {m..n}  Type
nat_plus	Def   == {i:| 0<i }
	Thm*    Type

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