ProofBase.get_append_l: law of lawful-arrays@0.1.0.0
Import: import lawful-arrays@0.1.0.0/proof_base.bend as ProofBase
Lines 312-319 of lawful-arrays@0.1.0.0/proof_base.bend: https://jend.leeeet.dev/read.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&start_line=312&end_line=319

import Base

# Before index length(xs), xs ++ ys reads like xs.
law get_append_l:
  for -A: Data
  for +xs: List<&2, A>
  for +ys: List<&2, A>
  for +i: Nat
  for e: {Nat.is_lt(i, List.length(&2, A, xs)) == True{} : Bool}
  {List.get(&2, A, List.append(&2, A, xs, ys), i) == List.get(&2, A, xs, i) : Maybe<&2, A>}

Uses (10):
  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=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.get
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.length
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  https://jend.leeeet.dev/definition.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&name=lt_zero_absurd