English

The Rademacher cotype of operators from $l_\infty^N$

Functional Analysis 2008-02-03 v2

Abstract

We show that for any operator T:lNYT:l_\infty^N\to Y, where YY is a Banach space, that its cotype 2 constant, K2(T)K_2(T), is related to its (2,1)(2,1)-summing norm, π2,1(T)\pi_{2,1}(T), by K2(T)cloglogNπ2,1(T)K_2(T) \le c \log\log N \pi_{2,1}(T) . Thus, we can show that there is an operator T:C(K)YT:C(K)\to Y that has cotype 2, but is not 2-summing.

Keywords

Cite

@article{arxiv.math/9201207,
  title  = {The Rademacher cotype of operators from $l_\infty^N$},
  author = {Stephen J. Montgomery-Smith and Michel Talagrand},
  journal= {arXiv preprint arXiv:math/9201207},
  year   = {2008}
}