ProofList.join_push: law of lawful-fields@0.1.1.0
Import: import lawful-fields@0.1.1.0/proof_list.bend as ProofList
Lines 120-124 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=120&end_line=124

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

law join_push:
  for +x: U32
  for +r: List<&2, List<&2, U32>>
  for +sep: U32
  {F.join(F.split.push(x, r), sep) == x <> F.join(r, sep) : List<&2, U32>}

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  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=join
  https://jend.leeeet.dev/definition.txt?path=lawful-fields@0.1.1.0/defs.bend&name=split.push