Majorizing measures and proportional subsets of bounded orthonormal systems

Olivier Guedon, Shahar Mendelson, Alain Pajor +1

In this article we prove that for any orthonormal system $(\vphi_j)_{j=1}^n \subset L_2$ that is bounded in $L_{\infty }$, and any $1<k<n$, there exists a subset $I$ of cardinali…