A note on subgaussian estimates for linear functionals on convex bodies

Abstract

We give an alternative proof of a recent result of Klartag on the existence of almost subgaussian linear functionals on convex bodies. If K is a convex body in R n with volume one and center of mass at the origin, there exists x 6 0 such that |{y ∈ K : |h y,xi| > tkh� ,xik 1}| 6 exp(−ct 2 /log 2 (t + 1)) for all t > 1, where c > 0 is an absolute constant. The proof is based on the study of the Lq–centroid bodies of K. Analogous results hold true for general log-concave measures.