List.length_cons: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/list.bend as List
Lines 469-475 of bend-mathlib@0.8.1.0/list.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/list.bend&start_line=469&end_line=475

import Base

# A cons is one longer than its tail.
law length_cons:
  for -a: Quant
  for -A: Kind(a)
  for -x: A
  for -xs: List<a, A>
  {List.length(a, A, x <> xs) == 1n+List.length(a, A, xs) : Nat}

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.length
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat