Inverse theorem for trigonometric approximation
= Inverse theorem for trigonometric approximation
For periodic uniform approximation,
$$
\omega(f,n^{-1})\leq\frac Cn\sum_{\nu=0}^nE_\nu(f).
$$
= Inverse theorem for trigonometric approximation
For periodic uniform approximation,
$$
\omega(f,n^{-1})\leq\frac Cn\sum_{\nu=0}^nE_\nu(f).
$$