“…These include the unit balls of ℓ p -norms on R n and some generalizations, and the effect of vanishing curvature on the error estimates have been investigated extensively in e.g. [Kr2], [Kr3], [Kr4], [KN1], [KN2], [No], [Pe1], [Pe2], [R1], [R2], [R3] and [R4]. It is natural to consider the following considerably more general set-up.…”