J. Peters et U. Reif, Least squares approximation of Bezier coefficients provides best degree reduction in the L-2-norm, J APPROX TH, 104(1), 2000, pp. 90-97
Given a polynomial p in d variables and of degree ii we want to find the be
st L-2-approximation over a d-simplex from polynomials of degree m < n. Thi
s problem is shown to be equivalent to the problem of finding the best Eucl
idean approximation of the Bernstein-Bezier coefficients of p from the spac
e of degree-raised Bernstein-Bezier coefficients of polynomials of degree m
. (C) 200 Academic Press.