Some definitions of interest.
is_prime_factorization	Def  is_prime_factorization(a; b; f) == i:{a..b}. 0<f(i)  prime(i)
	Thm*  a,b:, f:({a..b}). is_prime_factorization(a; b; f)  Prop
prime_nats	Def  Prime == {x:| prime(x) }
nat	Def   == {i:| 0i }
	Thm*    Type
prime_mset_complete	Def  prime_mset_complete(f)(x) == if is_prime(x) f(x) else 0 fi
	Thm*  f:(Prime). prime_mset_complete(f)

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