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arXiv · 1610.04023

The variance conjecture on hyperplane projections of l_p^n balls

David Alonso-Gutiérrez·Jesús Bastero
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Abstract

We show that for any $1\leq p\leq\infty$, the family of random vectors uniformly distributed on hyperplane projections of the unit ball of $\ell_p^n$ verify the variance conjecture $$ \textrm{Var}\,|X|^2\leq C\max_{\xi\in S^{n-1}}\mathbb{E}\langle X,\xi\rangle^2\mathbb{E}|X|^2, $$ where $C$ depends on $p$ but not on the dimension $n$ or the hyperplane. We will also show a general result relating the variance conjecture for a random vector uniformly distributed on an isotropic convex body and the variance conjecture for a random vector uniformly distributed on any Steiner symmetrization of it. As a consequence we will have that the class of random vectors uniformly distributed on any Steiner symmetrization of an $\ell_p^n$-ball verify the variance conjecture.

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David Alonso-Gutiérrez, Jesús Bastero. 2016-10-13. The variance conjecture on hyperplane projections of l_p^n balls. https://arxiv.org/abs/1610.04023

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