English

A Beckmann boundary form of Talagrand's conjecture on the discrete cube

Classical Analysis and ODEs 2026-06-30 v1 Functional Analysis Probability

Abstract

We introduce the Beckmann boundary of a Boolean function B(f)=infdivV=LfEV(x)2. \mathsf{B}(f)=\inf_{\operatorname{div} V=Lf}\mathbb E\|V(x)\|_2. Here L=iDi,Dif(x)=f(x)f(xi)2, L=\sum_iD_i,\qquad D_i f(x)=\frac{f(x)-f(x^{\oplus i})}{2}, and divV(x)=i(Vi(x)Vi(xi))\operatorname{div} V(x)=\sum_i (V_{i}(x)-V_{i}(x^{\oplus i})). This nonlocal quantity is no larger than the usual two-sided, one-sided, colored, optimized colored, or optimized fractional colored boundaries. Nevertheless, every nonconstant Boolean ff satisfies B(f)Var(f)log ⁣(1+1iInfi(f)2). \mathsf{B}(f)\gtrsim \operatorname{Var}(f) \sqrt{\log\!\left(1+\frac{1}{\sum_i\operatorname{Inf}_i(f)^2}\right)}. We also prove strong one-sided fractional spectral estimates. If A{1,1}nA\subset\{-1,1\}^n and hA(x)=#{i:xA, xiA}, h_{A}(x)=\#\{i:x\in A,\ x^{\oplus i}\notin A\}, then, for 0<α<10<\alpha<1, SSα1A^(S)2αEωα(hA), \sum_{S\ne\varnothing}|S|^\alpha\widehat{\mathbf 1_{A}}(S)^2 \lesssim_\alpha \mathbb E\omega_\alpha(h_{A}), where ωα(m)=m\omega_\alpha(m)=\sqrt m for α<1/2\alpha<1/2, ω1/2(m)=mlog(e+m)\omega_{1/2}(m)=\sqrt m\log(e+m), and ωα(m)=mα\omega_\alpha(m)=m^\alpha for α>1/2\alpha>1/2. These profiles are sharp, up to α\alpha-dependent constants, for majority. We also show that the comparison is genuinely nonreversible: an explicit quotient-cube family makes the optimized fractional, and hence optimized colored, boundary exceed B\mathsf{B} by a factor logn\gtrsim\sqrt{\log n}. We further obtain a driftless Bernstein-multiplier inequality.

Keywords

Cite

@article{arxiv.2606.31961,
  title  = {A Beckmann boundary form of Talagrand's conjecture on the discrete cube},
  author = {Paata Ivanisvili and Xinyuan Xie and Haonan Zhang},
  journal= {arXiv preprint arXiv:2606.31961},
  year   = {2026}
}

Comments

35 pages, 1 figure