English
For any a, IsPure (pure a).
Русский
Для любого a выполняется IsPure(pure a).
LaTeX
$$$\mathrm{IsPure}(\mathrm{pure}(a))$$$
Lean4
instance : LawfulMonad Semiquot :=
LawfulMonad.mk' (pure_bind := fun {α β} x f => ext.2 <| by simp) (bind_assoc := fun {α β} γ s f g =>
ext.2 <| by
simp only [bind_def, mem_bind]
exact fun c => ⟨fun ⟨b, ⟨a, as, bf⟩, cg⟩ => ⟨a, as, b, bf, cg⟩, fun ⟨a, as, b, bf, cg⟩ => ⟨b, ⟨a, as, bf⟩, cg⟩⟩)
(id_map := fun {α} q => ext.2 <| by simp) (bind_pure_comp := fun {α β} f s => ext.2 <| by simp [eq_comm])