Define the Natural numbers recursively by Natural ::= Zero|(Succ Natural) Assume functions (Succ n), (Pred n), (Zero? n) with Axioms o (Zero? Zero) #t [Zero-true axiom] o (Zero? (Succ n)) #f [Zero-false axiom] o (Pred Zero) Zero o (Succ (Pred n)) n (Pred (Succ n)) for n zero. [Succ-Pred axiom] o You may also use the if axioms. • Define the Plus function (define (Plus m n) (if (Zero? m) n (Succ (Plus (Pred m) n)))) • Prove by equational reasoning and Structural Induction that (Plus m Zero) m.