4 papers
A Beckmann boundary form of Talagrand's conjecture on the discrete cube
Paata Ivanisvili, Xinyuan Xie, Haonan Zhang
We introduce the Beckmann boundary of a Boolean function \[ \mathsf{B}(f)=\inf_{\operatorname{div} V=Lf}\mathbb E\|V(x)\|_2. \] Here \[ L=\sum_iD_i,\qquad D_i f(x)=\frac{f(x)-f(x^{…
Sharp hypercontractivity for free orthogonal quantum groups of Kac type
Haonan Zhang
We prove that the normalized heat semigroup on every free orthogonal quantum group of Kac type satisfies hypercontractivity with the optimal time. More precis…
Sharp log-Sobolev inequalities on finite cyclic groups
Xinyuan Xie, Haonan Zhang
Let be the cyclic group equipped with the uniform probability measure , and let be the Laplacian with word length \[ Ï_n(k) = \min(k,n-k). \] We prove…
Sharp hypercontractivity for free group von Neumann algebras
Xinyuan Xie, Haonan Zhang
In this paper, we settle the problem of optimal hypercontractivity for free group von Neumann algebras. Namely, for and the free group on generators, we…