Nat :: *;
Nat = forall (natT::*) . natT -> (natT->natT) -> natT;

0 :: Nat;
0 = \ (natT::*) (zero::natT) (succ::natT->natT) -> zero;

Succ :: Nat -> Nat;
Succ n = \ (natT::*) (zero::natT) (succ::natT->natT) -> succ (n natT zero succ);

natprim :: forall (r::*) . (r->r) -> r -> Nat -> r;
natprim r succ zero n = n r zero succ;

add :: Nat -> Nat -> Nat;
add x y = x Nat y Succ;

mul :: Nat -> Nat -> Nat;
mul x y = x Nat 0 (add y);

power :: Nat -> Nat -> Nat;
power x y = y Nat (Succ 0) (mul x);

isZero :: Nat -> Bool;
isZero n = n Bool True (\ a::Bool -> False);

1 :: Nat;
1 = Succ 0;
2 :: Nat;
2 = Succ 1;
3 :: Nat;
3 = Succ 2;