ProofBase.get_append_r: law of lawful-arrays@0.1.0.0
Import: import lawful-arrays@0.1.0.0/proof_base.bend as ProofBase
Lines 330-338 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=330&end_line=338

import Base

# From index length(xs) on, xs ++ ys reads like ys.
law get_append_r:
  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)) == False{} : Bool}
  {List.get(&2, A, List.append(&2, A, xs, ys), i)
    == List.get(&2, A, ys, Nat.sub(i, List.length(&2, A, xs))) : Maybe<&2, A>}

Uses (13):
  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=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=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=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&name=sub_zero
  https://jend.leeeet.dev/definition.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&name=true_ne_false