Observational Banach Manifolds
  In this paper, the concept of selective real manifolds is extended. It is proved that the product of two selective Banach manifolds is a selective Banach manifold. The notion of the $\alpha$--level differentiation of the mappings between selective Banach manifolds is presented. Basic properties of $(r, \alpha)$--differentiable maps are studied. Tangent space for at a point of a selective Banach manifold is considered. 
Mohammad Mehrpoya, Mohammadreza Molaei
math.FA