∀ (α : Type u_1),
  (FreeAddSemigroup.lift (⇑AddMagma.FreeAddSemigroup.of ∘ FreeAddMagma.of)).comp
      (AddMagma.FreeAddSemigroup.lift FreeAddMagma.toFreeAddSemigroup) =
    AddHom.id (AddMagma.FreeAddSemigroup (FreeAddMagma α))