“…In [3], the function t~*t 4 was approximated on the unit circle by bivariate polynomials of total degree 7. From [12,18], the optimal error in (tl, t2) -=(cos ~b, sin 4)) is 2 -7 cos 8 q5 so that the same solution is obtained on a discrete set containing the extrema defined by q~ =jrc/8 (0 <j< 15). This occurs with m points equally spaced from 1 where m is a multiple of 16, which yields Ax ~ b with A e P," • 36 and b e R".…”