The weak and strong moments conjecture for log-concave random vectors

Let XX be a log-concave random vector and let \|\cdot\| be any norm. Its dual norm is defined by

z=supx1z,x.\|z\|_{\star}=\sup_{\|x\|\le1}|\langle z,x\rangle|.

Weak and strong moments conjecture. There exist C,c>0C,c>0 such that for any log-concave random vector XX and any norm \|\cdot\|,

(EXp)1/pCEX+csupz1(Ez,Xp)1/p.\left(\mathbb{E}\|X\|^p\right)^{1/p}\le C\,\mathbb{E}\|X\|+c\sup_{\|z\|_{\star}\le1}\left(\mathbb{E}\langle z,X\rangle^p\right)^{1/p}.

This proposes a universal comparison between strong moments of an arbitrary norm and one-dimensional weak moments. The source attributes the question to Latała and gives Gaussian and Rademacher analogues, but does not state a general resolution.

Sources & referencesView supporting material

Primary source

Olivier Guédon, “Concentration phenomena in high dimensional geometry”, arXiv:1310.1204 (2013).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.