∀ {k : Type u_1} {G : Type u_2} {H : Type u_3} [inst : AddCommMonoid k] (f : G ≃ H) (a : G) (b : k),
  SkewMonoidAlgebra.equivMapDomain f (SkewMonoidAlgebra.single a b) = SkewMonoidAlgebra.single (f a) b