  Convergence and normal continuity analysis of a bivariate non-stationary
(level-dependent) subdivision scheme for 2-manifold meshes with arbitrary
topology is still an open issue. Exploiting ideas from the theory of
asymptotically equivalent subdivision schemes, in this paper we derive new
sufficient conditions for establishing convergence and normal continuity of any
rotationally symmetric, non-stationary, subdivision scheme near an
extraordinary vertex/face.
