Iterated Tikhonov spectral filter
= Iterated Tikhonov spectral filter
{title2=$g_k(\lambda)=[1-(1+\tau\lambda)^{-k}]/\lambda$}
The implicit iteration $(I+\tau K^*K)u_{k+1}=u_k+\tau K^*f$, starting from zero, multiplies each data <singular vector> by $[1-(1+\tau\sigma^2)^{-k}]/\sigma$. Its <operator norm> is at most $\sqrt{k\tau}$.