String.is_empty_iff_length_eq_zero_sym: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/string.bend as String
Lines 648-651 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=648&end_line=651

import Base

# A string is empty exactly when its length is zero, reversed to rewrite toward the simple side.
law is_empty_iff_length_eq_zero_sym:
  for s: String
  {Nat.is_eq(String.length(s), 0n) == String.is_empty(s) : Bool}

Uses (7):
  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=Nat.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.is_empty
  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=is_empty_iff_length_eq_zero