Bitsv.cbit: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/secp256k1/bitsv.bend as Bitsv
Lines 136-143 of bend-collections-laws-crypto@1.0.0.0/proofs/crypto/secp256k1/bitsv.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/secp256k1/bitsv.bend&start_line=136&end_line=143

import Base
import bend-collections-laws-crypto@1.0.0.0/proofs/lib/nat.bend as N

def cbit(b: Nat, +hb: {Nat.is_lt(b, 2n) == True{} : Bool}) -> {Nat.add(Nat.sub(1n, b), b) == 1n : Nat}:
  match b:
    case 0n:
      {==}
    case 1n:
      {==}
    case 2n+ +k:
      Empty.absurd({Nat.add(Nat.sub(1n, 2n+k), 2n+k) == 1n : Nat}, N.lt_zero_absurd(k, hb))

Uses (7):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Empty.absurd
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/lib/nat.bend&name=lt_zero_absurd