We study the following modification of a linear subdivision scheme
S: let
M be a surface embedded in Euclidean space, and
P a smooth projection mapping onto
M. Then the
P-projection analogue of
S is defined as
T :=
P ◦
S. As it turns out, the smoothness of the scheme
T is always at least as high as the smoothness of the underlying scheme
S or the smoothness of
P minus 1, whichever is lower. To prove this we use the method of proximity as introduced by Wallner et al. (Constr Approx
24(3):289–318, 2006; Comput Aided Geom Design 22(7):593–622, 2005). While smoothness equivalence results are already available
for interpolatory schemes
S, this is the first result that confirms smoothness equivalence properties of arbitrary order for general non-interpolatory
schemes.
Mathematics Subject Classification (2000) 41AXX - 41A25 - 53B - 22E