English

Haar basis testing

Functional Analysis 2024-10-21 v2

Abstract

We show that for two doubling measures σ\sigma and ω\omega on Rn\mathbb{R}^{n} and any fixed dyadic grid D\mathcal{D} in Rn\mathbb{R}^{n}, NRλ,n(σ,ω)HRλ,nD,glob(σ,ω)+HRλ,nD,glob(ω,σ) , \mathfrak{N}_{\mathbf{R}^{\lambda, n}}\left( \sigma,\omega\right) \approx\mathfrak{H}_{\mathbf{R}^{\lambda, n}}^{\mathcal{D},\operatorname*{glob}}\left( \sigma,\omega\right) +\mathfrak{H}_{\mathbf{R}^{\lambda, n}}^{\mathcal{D},\operatorname*{glob}}\left( \omega, \sigma\right) \ , where NRλ,n(σ,ω)\mathfrak{N}_{\mathbf{R}^{\lambda, n}} (\sigma, \omega) denotes the L2(σ)L2(ω)L^2 (\sigma) \to L^2 (\omega) operator norm of the vector-Riesz transform Rλ,n\mathbf{R}^{\lambda, n} of fractional order λ1\lambda \neq 1, and HRλ,nD,glob(σ,ω)supIDRλ,nhIσL2(ω) , \mathfrak{H}_{\mathbf{R}^{\lambda,n}}^{\mathcal{D},\operatorname*{glob}}\left( \sigma,\omega\right) \equiv\sup_{I\in\mathcal{D}}\left\Vert \mathbf{R}^{\lambda,n} h_{I}^{\sigma}\right\Vert _{L^{2}\left( \omega\right) }\ , is the global Haar testing characteristic for Rλ,n\mathbf{R}^{\lambda,n} on the grid D\mathcal{D}, and {hIσ}ID\left\{ h_{I}^{\sigma}\right\} _{I\in\mathcal{D}} is the weighted Haar orthonormal basis of L2(σ)L^{2}\left( \sigma\right) arising in the work of Nazarov, Treil and Volberg. We also show this theorem extends more generally to weighted Alpert wavelets which replace the weighted Haar wavelets in the proofs of some recent two-weight T1T1 theorems. Finally, we briefly pose these questions in the context of orthonormal bases in arbitrary Hilbert spaces.

Keywords

Cite

@article{arxiv.2309.03743,
  title  = {Haar basis testing},
  author = {Michel Alexis and Jose Luis Luna-Garcia and Eric T. Sawyer},
  journal= {arXiv preprint arXiv:2309.03743},
  year   = {2024}
}

Comments

22 pages + references. Due to a gap in a previous version of [SaWi], main results weakened to only consider p=2 and the vector Riesz transform. We also carry out a similar analysis for the Alpert wavelets

R2 v1 2026-06-28T12:15:21.174Z