Some $s$-numbers of an integral operator of Hardy type in Banach function spaces

Let $s_{n}(T)$ denote the $n$th approximation, isomorphism, Gelfand, Kolmogorov or Bernstein number of the Hardy-type integral operator $T$ given by $Tf(x)=v(x)\int_{a}^{x}u(t)f(t)dt,\,\,\,x\in(a,b)\,\,(-\infty<a<b<+\infty)$ and mapping a Banach function space $E$ to itself. We investigate some geometrical properties of $E$ for which $C_{1}\int_{a}^{b}u(x)v(x)dx \leq\limsup\limits_{n\rightarrow\infty}ns_{n}(T) \leq \limsup\limits_{n\rightarrow\infty}ns_{n}(T)\leq C_{2}\int_{a}^{b}u(x)v(x)dx$ under appropriate conditions on $u$ and $v.$ The constants $C_{1},C_{2}>0$ depend only on the space $E.$

No reviews yet.

No comments yet.