Some definitions of interest.
assert	Def b == if b True else False fi
	Thm* b:. b  Prop
lt_int	Def i<j == if i<j true ; false fi
	Thm* i,j:. (i<j)

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