Analytic aspects of the dilation inequality for symmetric convex sets in Euclidean spaces

Abstract

We discuss an analytic form of the dilation inequality with respect to a probability measure for symmetric convex sets in Euclidean spaces, which is a counterpart of analytic aspects of Cheeger’s isoperimetric inequality. We show that the dilation inequality for symmetric convex sets is equivalent to a certain bound of the relative entropy for even quasi-convex functions, which is close to the logarithmic Sobolev inequality or Cramér–Rao inequality. As corollaries, we investigate the reverse Shannon inequality, logarithmic Sobolev inequality, Kahane–Khintchine inequality, deviation inequality and isoperimetry. We also give new probability measures satisfying the dilation inequality for symmetric convex sets via bounded perturbations and tensorization.