fact: Definition ack'(n: nat): nat -> nat -> nat := Nat.recursion (fun a b => S b) (fun (pred0: nat) (rec0: nat -> nat -> nat) => Nat.recursion (Nat.recursion (fun (m: nat) => m) (fun (pred: nat) (rec: nat -> nat) (m: nat) => S (rec m))) (fun (pred: nat) (rec: nat -> nat -> nat) => (fun a b => Nat.recursion 1 (fun pred1 rec1 => rec a rec1) b)) pred0) n.
imports: Arith Lia List FunctionalExtensionality