English

Existence and Spectrality of random measures generated by infinite convolutions

Functional Analysis 2025-04-23 v1

Abstract

In this paper, we construct a class of random measures μn\mu^{\mathbf{n}} by infinite convolutions. Given infinitely many admissible pairs {(Nk,Bk)}k=1\{(N_{k}, B_{k})\}_{k=1}^{\infty} and a positive integral sequence n={nk}k=1\boldsymbol{n}=\{n_{k}\}_{k=1}^{\infty}, for every ωNN\boldsymbol{\omega}\in \mathbb{N}^{\mathbb{N}}, we write μn(ω)=δNω1n1Bω1δNω1n1Nω2n2Bω2\mu^{\mathbf{n}}(\boldsymbol{\omega}) = \delta_{N_{\omega_{1}}^{-n_{1}}B_{\omega_{1}}} * \delta_{N_{\omega_{1}}^{-n_{1}}N_{\omega_{2}}^{-n_{2}}B_{\omega_{2}}} * \cdots. If nk=1n_{k}=1 for k1k\geq 1, write μ(ω)=μn(ω)\mu(\boldsymbol{\omega})=\mu^{\mathbf{n}}(\boldsymbol{\omega}). First, we show that the mapping μn:(ω,B)μn(ω)(B)\mu^{\mathbf{n}}: (\boldsymbol{\omega}, B) \mapsto \mu^{\mathbf{n}}(\boldsymbol{\omega})(B) is a random measure if the family of Borel probability measures {μ(ω):ωNN}\{\mu(\boldsymbol{\omega}) : \boldsymbol{\omega} \in \mathbb{N}^{\mathbb{N}}\} is tight. Then, for every Bernoulli measure P\mathbb{P} on NN\mathbb{N}^{\mathbb{N}}, the random measure μn\mu^{\mathbf{n}} is also a spectral measure P\mathbb{P}-a.e.. If the positive integral sequence n\boldsymbol{n} is unbounded, the random measure μn\mu^{\mathbf{n}} is a spectral measure regardless of the measures on the sequence space NN\mathbb{N}^{\mathbb{N}}. Moreover, we provide some sufficient conditions for the existence of the random measure μn\mu^{\boldsymbol{n}}. Finally, we verify that random measures have the intermediate-value property.

Keywords

Cite

@article{arxiv.2504.15744,
  title  = {Existence and Spectrality of random measures generated by infinite convolutions},
  author = {Junjie Miao and Hongyi Liu and Hongbo Zhao},
  journal= {arXiv preprint arXiv:2504.15744},
  year   = {2025}
}