characterized in that there exist holomorphic function g = f − 1 {\displaystyle g=f^{-1}} : f ( g ( z ) ) = z ∀ z ∈ B {\displaystyle f{\big (}g(z){\big )}\!=\!z~\forall z\in B~} and g ( f ( z ) ) = z ∀ z ∈ A {\displaystyle g{\big (}f(z){\big )}\!=\!z~\forall z\in A~} . [d] [e]