Memory.length_drop: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/argon2/memory.bend as Memory
Lines 47-54 of bend-collections-laws-crypto@1.0.0.0/proofs/crypto/argon2/memory.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/argon2/memory.bend&start_line=47&end_line=54

import Base
import bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend as SC

def length_drop(+xs: List<&2, U32>, +n: Nat) -> {SC.length(U32, SC.drop(U32, xs, n)) == Nat.sub(SC.length(U32, xs), n) : Nat}:
  match xs n:
    case Nil{} _:
      Equal.sym(Nat, Nat.sub(0n, n), 0n, zsub(n))
    case Con{h, t} 0n:
      {==}
    case Con{+h, +t} 1n+ +p:
      length_drop(t, p)

Uses (8):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/argon2/memory.bend&name=zsub
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend&name=drop
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend&name=length