N. Nikolski

activity

20102020

collaborators

4 papers

math.CA2020

Sign intermixing for Riesz bases and frames measured in the Kantorovich-Rubinstein norm

Nikolai Nikolski, Alexander Volberg

We measure a sign interlacing phenomenon for Bessel sequences $(u_{k})$ in $L^{2}$ spaces in terms of the Kantorovich--Rubinstein mass moving norm $∥ u_{k} ∥_{K R}$ . Our m…

math.FA2020

Szegő-type limit theorems for "multiplicative Toeplitz" operators and non-Følner approximations

Nikolai Nikolski, Alexander Pushnitski

We discuss an analogue of the First Szegő Limit Theorem for multiplicative Toeplitz operators and highlight the role of the multliplicative Følner condition in this topic.

math.FA2018

On the Sign Distributions of Hilbert Space Frames

Nikolai Nikolski, Alexander Volberg

We show that the positive and negative parts $u_{k}^{\pm}$ of any frame in a real $L^{2}$ space with respect to a continuous measure have both "infinite $l^{2}$ masses": 1) alw…

math.FA2010

Invertibility threshold for $H^{\infty}$ trace algebras, and effective matrix inversions

Nikolai Nikolski, Vasily Vasyunin

For a given $δ$ , $0 < δ < 1$ , a Blaschke sequence $σ = {λ_{j}}$ is constructed such that every function $f$ , $f \in H^{\infty}$ , having $δ < δ_{f} = in f_{λ \in σ} ∣ f (λ) ∣ \leq ∥ f ∥_{\infty} \leq 1$ is inve…

Sign intermixing for Riesz bases and frames measured in the Kantorovich-Rubinstein norm

Szegő-type limit theorems for "multiplicative Toeplitz" operators and non-Følner approximations

On the Sign Distributions of Hilbert Space Frames

Invertibility threshold for H∞ trace algebras, and effective matrix inversions

Invertibility threshold for $H^{\infty}$ trace algebras, and effective matrix inversions