English

Comparing gaussian and Rademacher cotype for operators on the space of continous functions

Functional Analysis 2016-09-06 v1

Abstract

We will prove an abstract comparision principle which translates gaussian cotype in Rademacher cotype conditions and vice versa. More precisely, let 2 ⁣< ⁣q ⁣< ⁣2\!<\!q\!<\!\infty and T:C(K)FT:\,C(K)\,\to\,F a linear, continous operator. T is of gaussian cotype q if and only if ( \summ_1^n (\frac{|| Tx_k||_F}{\sqrt{\log(k+1)}})^q )^{1/q} \, \le c || \summ_1^n \varepsilon_k x_k ||_{L_2(C(K))} , for all sequences with (Txk)1n(|| Tx_k ||)_1^n decreasing. T is of Rademacher cotype q if and only if (\summ_1^n (|| Tx_k||_F \,\sqrt{\log(k+1)})^q )^{1/q} \, \le c || \summ_1^n g_k x_k ||_{L_2(C(K))} , for all sequences with (Txk)1n(||Tx_k ||)_1^n decreasing. Our methods allows a restriction to a fixed number of vectors and complements the corresponding results of Talagrand.

Keywords

Cite

@article{arxiv.math/9302206,
  title  = {Comparing gaussian and Rademacher cotype for operators on the space of continous functions},
  author = {Marius Junge},
  journal= {arXiv preprint arXiv:math/9302206},
  year   = {2016}
}