English
There is a lawful identity element for merge f with none; none acts as a neutral element for merge.
Русский
Для merge f существует нейтральный элемент, равный none; none является нейтральным элементом для объединения.
LaTeX
$$$ \mathrm{Std.LawfulIdentity} (\mathrm{Option.merge}\ f) \mathrm{none}$$$
Lean4
@[deprecated lawfulIdentity_merge (since := "2025-06-03")]
theorem merge_isId (f : α → α → α) : Std.LawfulIdentity (merge f) none :=
lawfulIdentity_merge f