“…The quality of the approximation depends on the norm. For several decades polynomial degree reduction has attracted considerable interest with respect to different norms: e.g., L ∞ -norm [8,24], L 2 -norm [14,18,19], L 1 -norm [12], L p -norm [6], Jacobi norms [2,25] as well as to different boundary constraints [1,16,17,21,26].…”