1 let id = << fun x -> x >>
2 (* Imported and traduced from CCT *)
3 let zero = << fun s -> fun z -> z >>
4 let succ = << fun n -> fun s -> fun z -> s n >>
5 let one = << $succ$ $zero$ >>
6 let iota = << fun x -> z >>
7 let rho = << fun m -> fun r -> (s m (m r $iota$ r)) >>
9 << fun n -> fun s -> fun z -> n $rho$ $iota$ $rho$ >>
10 let plus = << fun n -> fun m -> $rec_nat$ n (fun n -> fun p -> $succ$ p) m >>
11 let times = << fun n -> fun m -> $rec_nat$ n (fun n -> fun p -> $plus$ m p) $zero$ >>
12 let fact = << fun n -> $rec_nat$ n (fun n -> fun p -> $times$ ($succ$ n) p) $one$ >>