Entropy and approximation numbers of embeddings of function spaces with Muckenhoupt weights, I.
We determine the asymptotic behavior of the entropy numbers of diagonal operators D: lp → lq, (xk) → (skxk), 0 < p,q ≤ ∞, under mild regularity and decay conditions on the generating sequence (σk). Our results extend the known estimates for polynomial and logarithmic diagonals (σk). Moreover, we also consider some exotic intermediate examples like (σk)=exp(-√log k).
In this paper we show that a Rosenthal operator factors through a Banach space containing no isomorphs of l1.