G. Belitskii, V. Rayskin Equivalence of families of diffeomorphisms on Banach spaces (261K, pdf) ABSTRACT. We consider two families of $C^\infty$-diffeomorphisms (with hyperbolic linear part at $0$) on a Banach space. Suppose that these two families formally conjugate at $0$. We prove that they admit local conjugation, which is infinitely smooth in both, the space variable and the family parameter. In particular, subject to non-resonance condition, there exists a family of local $C^\infty$ linearizations of the family of diffeomorphisms. The linearizing family has $C^\infty$ smoothness in parameter. The results are proved under the assumption that the Banach space allows a special extension of the maps. We discuss corresponding properties of Banach spaces.