#A: A function φ definable explicitly from functions Ψ and constants q1, ... qn is primitive recursive in Ψ.
#B: The finite sum Σy<z ψ(x, y) and product Πy<zψ(x, y) are primitive recursive in ψ.
#C: A predicate P obtained by substituting functions χ1,..., χm for the respective variables of a predicate Q is primitive recursive in χ1,..., χm, Q.
#D: The following predicates are primitive recursive in Q and R: