English
Related papers

Related papers: On a class of subdiagonal algebras

200 papers

Unbounded convergences have been applied successfully to locally solid topologies on vector lattices. In the present paper, we first expose several properties of various classes of Riesz pseudonorms on vector lattices. We accomplish this by…

Functional Analysis · Mathematics 2019-10-16 Nazife Erkurşun-Özcan , Niyazi Anıl Gezer

Let $(\mathbb{X},\,d,\,\mu)$ be a space of homogeneous type in the sense of Coifman and Weiss, $X$ be a ball quasi-Banach function space on $\mathbb{X}$, $L$ be a non-negative self-adjoint operator on $L^2(\mathbb{X})$, and assume that, for…

Functional Analysis · Mathematics 2025-03-06 Xiong Liu , Wenhua Wang , Tiantian Zhao

In this article, we study geometric aspects of semi-arithmetic Riemann surfaces by means of number theory and hyperbolic geometry. First, we show the existence of infinitely many semi-arithmetic Riemann surfaces of various shapes and prove…

Geometric Topology · Mathematics 2020-09-02 Gregory Cosac , Cayo Dória

Let $\mathcal{S}_H^0(K)$, $K\ge 1$, be the class of normalized $K$-quasiconformal harmonic mappings in the unit disk. We obtain Baernstein type extremal results for the analytic and co-analytic parts of functions in the geometric subclasses…

Complex Variables · Mathematics 2025-10-21 Suman Das , Jie Huang , Antti Rasila

For $2\le p<\infty$ we show the lower estimates \[ \|A^{\frac 12}x\|_p \kl c(p)\max\{\pl \|\Gamma(x,x)^{{1/2}}\|_p,\pl \|\Gamma(x^*,x^*)^{{1/2}}\|_p\} \] for the Riesz transform associated to a semigroup $(T_t)$ of completely positive maps…

Operator Algebras · Mathematics 2008-06-13 Marius Junge , Tao Mei

It is well-known that the theories of semi-vector spaces and semi-algebras -- which were not much studied over time -- are utilized/applied in Fuzzy Set Theory in order to obtain extensions of the concept of fuzzy numbers as well as to…

General Mathematics · Mathematics 2021-11-23 Giuliano G. La Guardia , Jocemar de Q. Chagas , Ervin K. Lenzi , Leonardo Pires

In this paper we present a new extension of the theory of well-bounded operators to cover operators with complex spectrum. In previous work a new concept of the class of absolutely continuous functions on a nonempty compact subset $\sigma$…

Functional Analysis · Mathematics 2013-11-13 Brenden Ashton , Ian Doust

In this paper we introduce generalized grand Morrey spaces in the framework of quasimetric measure spaces, in the spirit of the so-called grand Lebesgue spaces. We prove a kind of reduction lemma which is applicable to a variety of…

Functional Analysis · Mathematics 2012-04-11 Vakhtang Kokilashvili , Alexander Meskhi , Humberto Rafeiro

We investigate the Hardy space $H^1_L$ associated with a self-adjoint operator $L$ defined in a general setting in [S. Hofmann, et. al., Hardy spaces associated to non-negative self-adjoint operators satisfying Davies-Gaffney estimates,…

Functional Analysis · Mathematics 2023-10-31 Marcin Preisner , Adam Sikora , Lixin Yan

We consider continuous semigroups of analytic functions $\{\Phi_t\}_{t\geq0}$ in the so-called Gordon-Hedenmalm class $\mathcal{G}$, that is, the family of analytic functions $\Phi:\mathbb C_+\to \mathbb C_+$ giving rise to bounded…

Functional Analysis · Mathematics 2022-03-11 Manuel D. Contreras , Carlos Gómez-Cabello , Luis Rodríguez-Piazza

The authors study Hardy spaces, of arbitrary order, on a space of homogeneous type. This extends earlier work that treated only $H^p$ for $p$ near 1. Applications are given to the boundedness of certain singular integral operators,…

Functional Analysis · Mathematics 2016-09-06 Steven G. Krantz , Song-Ying Li

Given a frequency $\lambda=(\lambda_n)$, we study when almost all vertical limits of a $\mathcal{H}_1$-Dirichlet series $\sum a_n e^{-\lambda_ns}$ are Riesz-summable almost everywhere on the imaginary axis. Equivalently, this means to…

Functional Analysis · Mathematics 2019-08-20 Andreas Defant , Ingo Schoolmann

This paper provides a class of complex symmetric weighted composition operators on $H^2(\mathbb{D})$ to includes the unitary subclass, the Hermitian subclass and the normal subclass obtained by Bourdon and Noor. A characterization of…

Functional Analysis · Mathematics 2018-12-27 Cao Jiang , Shi-An Han , Ze-Hua Zhou

The objective of this article is to study nearly invariant subspaces of the backward shift operator on the real Hardy space. We also investigate nearly invariant subspaces with finite defect, and as a consequence, provide a characterization…

Functional Analysis · Mathematics 2026-04-14 Arshad Khan , Sneh Lata , Dinesh Singh

To study operator algebras with symmetries in a wide sense we introduce a notion of {\em relative convolution operators} induced by a Lie algebra. Relative convolutions recover many important classes of operators, which have been already…

funct-an · Mathematics 2008-02-03 Vladimir V. Kisil

Associated to the class of restricted-weak type weights for the Hardy operator, we find a new class of Lorentz spaces for which the normability property holds. This result is analogous to the characterization given by Sawyer for the…

Classical Analysis and ODEs · Mathematics 2007-05-23 Joaquim Martin , Javier Soria

Loday's dendriform algebras and its siblings pre-Lie and zinbiel have received attention over the past two decades. In recent literature, there has been interest in a generalization of these types of algebra in which each individual…

Rings and Algebras · Mathematics 2020-07-14 Marcelo Aguiar

We exhibit a singly generated, semisimple commutative operator algebra with a contractive approximate identity, such that the spectrum of the generator is a null sequence and zero, but the algebra is not the closed linear span of the…

Operator Algebras · Mathematics 2014-10-28 David P. Blecher , Charles John Read

In the past decade there has been a flurry of activity at the intersection of spectral theory and symplectic geometry. In this paper we review recent results on semiclassical spectral theory for commuting Berezin-Toeplitz and…

Mathematical Physics · Physics 2013-03-12 Álvaro Pelayo

We study reflexivity and structure properties of operator algebras generated by representations of the discrete Heisenberg semi-group. We show that the left regular representation of this semi-group gives rise to a semi-simple reflexive…

Operator Algebras · Mathematics 2014-07-15 M. Anoussis , A. Katavolos , I. G. Todorov