∀ {α : Type u_1} [inst : AddCommGroup α] (ψ χ : AddChar α Circle),
  AddChar.toMonoidHomEquiv.symm (Circle.coeHom.comp (ψ + χ).toMonoidHom) =
    AddChar.toMonoidHomEquiv.symm (Circle.coeHom.comp (ψ + χ).toMonoidHom)