Smoothness of indicator functions of some sets in Wiener spaces

Let A be a ball in the classical Wiener space defined by the sup-norm or th e pseudo-Sobolev norm, then chi(A) is an element of E-alpha(P) for p alpha < 1 and chi(A) is not an element of E-alpha(P) for p alpha > 1. (C) 2000 Ed itions scientifiques et medicales Elsevier SAS.