LAWS.split_join: law of lawful-fields@0.1.1.0
Import: import lawful-fields@0.1.1.0/LAWS.bend as LAWS
Lines 84-88 of lawful-fields@0.1.1.0/LAWS.bend: https://jend.leeeet.dev/read.txt?path=lawful-fields@0.1.1.0/LAWS.bend&start_line=84&end_line=88

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

# Joining the pieces with the separator gives xs back.
law split_join:
  for xs: List<&2, U32>
  for sep: U32
  {F.join(F.split(xs, sep), sep) == xs : List<&2, U32>}

Uses (5):
  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
  https://jend.leeeet.dev/definition.txt?path=lawful-fields@0.1.1.0/proof_list.bend&name=split_join