def nat_decode

qasim-bend-kit@0.1.0.2 · proof/AES_CertificateProof.bend:84

import Base

84def nat_decode(+a: Nat, +b: Nat, code: nat_code(a, b)) -> {a == b : Nat}:
85    match a b:
86        case 0n 0n: {==}
87        case 0n 1n+q: Empty.absurd({a == b : Nat}, code)
88        case 1n+p 0n: Empty.absurd({a == b : Nat}, code)
89        case 1n+p 1n+q:
90            Equal.cong(Nat, Nat, value => 1n+value, p, q,
91                nat_decode(p, q, code))