ProofList.ends_join: law of lawful-fields@0.1.1.0
Import: import lawful-fields@0.1.1.0/proof_list.bend as ProofList
Lines 412-418 of lawful-fields@0.1.1.0/proof_list.bend: https://jend.leeeet.dev/read.txt?path=lawful-fields@0.1.1.0/proof_list.bend&start_line=412&end_line=418

import Base
import lawful-fields@0.1.1.0/defs.bend as F

law ends_join:
  for +ps: List<&2, List<&2, U32>>
  for +sep: U32
  for +from: Nat
  for +k: Nat
  for +h: {Nat.is_lt(k, List.length(&2, List<&2, U32>, ps)) == True{} : Bool}
  {List.get(&2, Nat, F.ends(ps, from), k) == Some{Nat.add(from, List.length(&2, U32, F.join(List.take(&2, List<&2, U32>, ps, Nat.add(k, 1n)), sep)))} : Maybe<&2, Nat>}

Uses (15):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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.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=List.take
  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.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=U32
  https://jend.leeeet.dev/definition.txt?path=lawful-fields@0.1.1.0/defs.bend&name=ends
  https://jend.leeeet.dev/definition.txt?path=lawful-fields@0.1.1.0/defs.bend&name=join
  https://jend.leeeet.dev/definition.txt?path=lawful-fields@0.1.1.0/proof_list.bend&name=ej
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/proof_nat.bend&name=add_one