“…In fact these nodes maintain the approximation quality of the 1D-version, 20 i.e, if f : [−1, 1] m −→ R is a regular function and Q Am,n,p,f denotes its interpolant in P Am,n,p , then lim n→∞ Q Am,n,p,f = f uniformly and (exponentially) fast. 20,66 In particular, choosing Euclidean degree p = 2 results in an "optimal" choice. 20,66 We incorporate these insights into the following definitions.…”