String.length_drop_sym: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/string.bend as String
Lines 691-695 of bend-mathlib@0.8.1.0/string.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/string.bend&start_line=691&end_line=695

import Base

# Dropping n characters leaves length - n of them, reversed to rewrite toward the simple side.
law length_drop_sym:
  for s: String
  for n: Nat
  {Nat.sub(String.length(s), n) == String.length(String.drop(s, n)) : Nat}

Uses (7):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.drop
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.length
  https://jend.leeeet.dev/definition.txt?path=bend-mathlib@0.8.1.0/string.bend&name=length_drop