fact: Fixpoint nVars (n: nat) : Terms n * Terms n:= match n with 0 => (Tnil, Tnil) | S n0 => (let (a,b) := nVars n0 in (Tcons (var (n0 + n0)) a, Tcons (var (S (n0 + n0))) b)) end.
imports: Coq(Ensembles Lists.List Arith) hydras.Ackermann(folProp)