Some definitions of interest.
prime_nats	Def  Prime == {x:| prime(x) }
nat	Def   == {i:| 0i }
	Thm*    Type
prime_decider	Def  is_prime(x) == prime_decider_exists{1:l}(x)
	Thm*  x:. is_prime(x)

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