Expositiones Mathematicae最新文献

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-21 DOI: 10.1016/j.exmath.2025.125692

William G. Bass, Jack S. Calcut

引用次数: 0

Expository article: “Bounded orthogonal systems and the Λ(p)-set problem” by Jean Bourgain 说明性文章：“有界正交系统和Λ(p)-集问题”，作者：Jean Bourgain

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-16 DOI: 10.1016/j.exmath.2025.125691

Hongki Jung , Bartosz Langowski , Alexander Ortiz , Truong Vu

引用次数: 0

A comprehensive approach to multifractal analysis 多重分形分析的综合方法

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-11 DOI: 10.1016/j.exmath.2025.125690

Zhiming Li , Bilel Selmi , Haythem Zyoudi

{"title":"A comprehensive approach to multifractal analysis","authors":"Zhiming Li , Bilel Selmi , Haythem Zyoudi","doi":"10.1016/j.exmath.2025.125690","DOIUrl":"10.1016/j.exmath.2025.125690","url":null,"abstract":"<div><div>This paper investigates how specific techniques have been broadened to suit more general contexts. Among them, multifractal analysis stands out for its adaptability and depth, presenting a unified framework to approach these generalizations. We examine the relative multifractal formalism within the context of metric spaces in a general way. The primary aim is to introduce a generalized concept of general relative multifractal Hausdorff and packing measures. In particular, we delve into the characteristics of the generalized multifractal Hausdorff and packing measures and analyze their impact on the broader multifractal spectrum functions. The investigation explores the connection between these generalized multifractal measures and the nature of general multifractal dimensions within this framework. Further, we establish an equivalence relation between general relative multifractal Hausdorff and packing measures by utilizing density theorems. Moreover, we study various properties of the generalized relative multifractal Hausdorff measures, packing measures, and pre-measures. Lastly, our work addresses the question of whether a subset in Euclidean space <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> with infinite positive Hausdorff measure can contain a compact set of positive finite general relative Hausdorff measures.</div></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"43 5","pages":"Article 125690"},"PeriodicalIF":0.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On a criterion for algebraic independence applied to continued fractions 应用于连分式的代数无关性判据

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-10 DOI: 10.1016/j.exmath.2025.125689

Gessica Alecci , Carsten Elsner

{"title":"On a criterion for algebraic independence applied to continued fractions","authors":"Gessica Alecci , Carsten Elsner","doi":"10.1016/j.exmath.2025.125689","DOIUrl":"10.1016/j.exmath.2025.125689","url":null,"abstract":"<div><div>From around 2010 onward, Elsner et al. <!-->developed and applied a method in which the algebraic independence of <span><math><mi>n</mi></math></span> quantities <span><math><mrow><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></math></span> over a field is transferred to further <span><math><mi>n</mi></math></span> quantities <span><math><mrow><msub><mrow><mi>y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></math></span> by means of a system of polynomials in <span><math><mrow><mn>2</mn><mi>n</mi></mrow></math></span> variables <span><math><mrow><msub><mrow><mi>X</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>X</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>,</mo><msub><mrow><mi>Y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>Y</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></math></span>. In this paper, we systematically study and explain this criterion and its variants. Moreover, we present new results concerning its application to periodic non-regular continued fractions, namely continued fractions with real numbers as partial quotients. We show that given a continued fraction of this type, this criterion can be applied to prove that not only are the convergents algebraically independent from each other, but they are also algebraically independent from the continued fraction.</div></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"43 5","pages":"Article 125689"},"PeriodicalIF":0.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Monoids, dynamics and Leavitt path algebras 一元群，动力学与Leavitt路径代数

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-09 DOI: 10.1016/j.exmath.2025.125684

Gene Abrams , Roozbeh Hazrat

引用次数: 0

Jordan homomorphisms on Hilbert C∗-modules Hilbert C * -模上的Jordan同态

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-03 DOI: 10.1016/j.exmath.2025.125687

Xiaofei Qi , Huimin Chen , Jinchuan Hou

引用次数: 0

The redundancy of Gabor type unitary systems on locally compact abelian groups 局部紧阿贝尔群上Gabor型酉系统的冗余性

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-03 DOI: 10.1016/j.exmath.2025.125686

Jingsheng Wang, Pengtong Li

引用次数: 0

Generalized Fermat equation: A survey of solved cases 广义费马方程：已解案例综述

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-03 DOI: 10.1016/j.exmath.2025.125688

Ashleigh Ratcliffe, Bogdan Grechuk

{"title":"Generalized Fermat equation: A survey of solved cases","authors":"Ashleigh Ratcliffe, Bogdan Grechuk","doi":"10.1016/j.exmath.2025.125688","DOIUrl":"10.1016/j.exmath.2025.125688","url":null,"abstract":"<div><div>Generalized Fermat equation (GFE) is the equation of the form <span><math><mrow><mi>a</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mi>b</mi><msup><mrow><mi>y</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>=</mo><mi>c</mi><msup><mrow><mi>z</mi></mrow><mrow><mi>r</mi></mrow></msup></mrow></math></span>, where <span><math><mrow><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>,</mo><mi>p</mi><mo>,</mo><mi>q</mi><mo>,</mo><mi>r</mi></mrow></math></span> are positive integers. If <span><math><mrow><mn>1</mn><mo>/</mo><mi>p</mi><mo>+</mo><mn>1</mn><mo>/</mo><mi>q</mi><mo>+</mo><mn>1</mn><mo>/</mo><mi>r</mi><mo><</mo><mn>1</mn></mrow></math></span>, GFE is known to have at most finitely many primitive integer solutions <span><math><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>,</mo><mi>z</mi><mo>)</mo></mrow></math></span>. A large body of the literature is devoted to finding such solutions explicitly for various six-tuples <span><math><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>,</mo><mi>p</mi><mo>,</mo><mi>q</mi><mo>,</mo><mi>r</mi><mo>)</mo></mrow></math></span>, as well as for infinite families of such six-tuples. This paper surveys the families of parameters for which GFE has been solved. Although the proofs are not discussed here, collecting these references in one place will make it easier for the readers to find the relevant proof techniques in the original papers. Also, this survey will help the readers to avoid duplicate work by solving the already solved cases.</div></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"43 4","pages":"Article 125688"},"PeriodicalIF":0.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Symmetrized pseudofunction algebras from Lp-representations and amenability of locally compact groups lp -表示的对称伪函数代数与局部紧群的可调性

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-02 DOI: 10.1016/j.exmath.2025.125685

Emilie Mai Elkiær

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Linearization of Lipschitz framings for Banach spaces Banach空间的Lipschitz框架的线性化

IF 0.8 4区数学

Expositiones Mathematicae Pub Date : 2025-04-01 DOI: 10.1016/j.exmath.2025.125680

Qiyao Bao , Deguang Han , Rui Liu , Jie Shen

{"title":"Linearization of Lipschitz framings for Banach spaces","authors":"Qiyao Bao , Deguang Han , Rui Liu , Jie Shen","doi":"10.1016/j.exmath.2025.125680","DOIUrl":"10.1016/j.exmath.2025.125680","url":null,"abstract":"<div><div>Nonlinear framings naturally appear in many applications where nonlinear procedures are necessary. This paper examines two basic issues involving the linearization of Lipschitz framings. We first prove that every Lipschitz framing induces a linear framing which shares the same synthesis operator, and consequently every Banach space admitting a Lipschitz framing has the bounded approximation property. Secondly, we examine the projection-valued dilations of Lipschitz operator-valued measures on Banach spaces. We prove that every Lipschitz operator-valued measure can induce an operator-valued measure by linearization, and every <span><math><mrow><mi>Lip</mi><mrow><mo>(</mo><mi>X</mi><mo>,</mo><mi>Y</mi><mo>)</mo></mrow></mrow></math></span>-valued measure has a projection-valued measure dilation by establishing a nonlinear version of minimal dilation theory. As examples, we discuss a concrete construction of the minimal dilation for the special case when the measure space is <span><math><mrow><mo>(</mo><mi>N</mi><mo>,</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>N</mi></mrow></msup><mo>)</mo></mrow></math></span>, and how nonlinear sampling naturally induces a Lipschitz framing.</div></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"43 4","pages":"Article 125680"},"PeriodicalIF":0.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0