Pub Date : 2024-09-04DOI: 10.1016/j.exmath.2024.125605
Rodrigo Duarte
The goal of this expository paper is to give a self-contained introduction to sparse domination. This is a method relying on techniques from dyadic Harmonic Analysis which has received a lot of attention in recent years. Essentially, it allows for a unified approach to proving weighted norm inequalities for a large variety of operators. In this work, we will introduce the basic ideas of dyadic Harmonic Analysis, which we use to build up to the main result we discuss on pointwise sparse domination, which is the Lerner–Ombrosi theorem. We also give applications of this theorem to some families of operators, mainly relating to singular integral operators. The text has been structured so as to motivate the introduction of new ideas through the lens of solving specific problems in Harmonic Analysis.
{"title":"An introduction to pointwise sparse domination","authors":"Rodrigo Duarte","doi":"10.1016/j.exmath.2024.125605","DOIUrl":"10.1016/j.exmath.2024.125605","url":null,"abstract":"<div><p>The goal of this expository paper is to give a self-contained introduction to sparse domination. This is a method relying on techniques from dyadic Harmonic Analysis which has received a lot of attention in recent years. Essentially, it allows for a unified approach to proving weighted norm inequalities for a large variety of operators. In this work, we will introduce the basic ideas of dyadic Harmonic Analysis, which we use to build up to the main result we discuss on pointwise sparse domination, which is the Lerner–Ombrosi theorem. We also give applications of this theorem to some families of operators, mainly relating to singular integral operators. The text has been structured so as to motivate the introduction of new ideas through the lens of solving specific problems in Harmonic Analysis.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 6","pages":"Article 125605"},"PeriodicalIF":0.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0723086924000720/pdfft?md5=45dd60e1ad35b7a191fa8e59cc8e5e5d&pid=1-s2.0-S0723086924000720-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142271041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1016/j.exmath.2024.125604
Jean-François Burnol
The harmonic sum of the integers which are missing given digits in a base is expressed as plus corrections indexed by the excluded digits and expressed as integrals involving the digamma function and a suitable measure. A number of consequences are derived, such as explicit bounds, monotony, series representations and asymptotic expansions involving the zeta values at integers, and suitable moments of the measure. In the classic Kempner case of and 9 as the only excluded digit, the series representation turns out to be exactly identical with a result obtained by Fischer already in 1993. Extending this work is indeed the goal of the present contribution.
在基数 b 中缺失 p 个给定数位的整数的谐和表示为 blog(b)/p 加上以缺失数位为索引的修正，并表示为涉及 digamma 函数和适当度量的积分。由此可以推导出许多结果，如明确的界限、单调性、涉及整数处zeta值的数列表示和渐近展开，以及量的适当矩。在 b=10 和 9 为唯一排除数字的经典坎普纳案例中，数列表示结果与费舍尔在 1993 年获得的结果完全相同。扩展这项工作正是本论文的目标。
{"title":"Digamma function and general Fischer series in the theory of Kempner sums","authors":"Jean-François Burnol","doi":"10.1016/j.exmath.2024.125604","DOIUrl":"10.1016/j.exmath.2024.125604","url":null,"abstract":"<div><p>The harmonic sum of the integers which are missing <span><math><mi>p</mi></math></span> given digits in a base <span><math><mi>b</mi></math></span> is expressed as <span><math><mrow><mi>b</mi><mo>log</mo><mrow><mo>(</mo><mi>b</mi><mo>)</mo></mrow><mo>/</mo><mi>p</mi></mrow></math></span> plus corrections indexed by the excluded digits and expressed as integrals involving the digamma function and a suitable measure. A number of consequences are derived, such as explicit bounds, monotony, series representations and asymptotic expansions involving the zeta values at integers, and suitable moments of the measure. In the classic Kempner case of <span><math><mrow><mi>b</mi><mo>=</mo><mn>10</mn></mrow></math></span> and 9 as the only excluded digit, the series representation turns out to be exactly identical with a result obtained by Fischer already in 1993. Extending this work is indeed the goal of the present contribution.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 6","pages":"Article 125604"},"PeriodicalIF":0.8,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240343","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}
Pub Date : 2024-08-07DOI: 10.1016/j.exmath.2024.125600
Charles H. Conley, William Goode
We present a general method for describing the annihilators of modules of Lie algebras under certain conditions, which hold for some tensor modules of vector field Lie algebras. As an example, we apply the method to obtain an efficient proof of previously known results on the annihilators of the bounded irreducible modules of .
{"title":"An approach to annihilators in the context of vector field Lie algebras","authors":"Charles H. Conley, William Goode","doi":"10.1016/j.exmath.2024.125600","DOIUrl":"https://doi.org/10.1016/j.exmath.2024.125600","url":null,"abstract":"We present a general method for describing the annihilators of modules of Lie algebras under certain conditions, which hold for some tensor modules of vector field Lie algebras. As an example, we apply the method to obtain an efficient proof of previously known results on the annihilators of the bounded irreducible modules of .","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"77 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142192927","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}
Pub Date : 2024-08-02DOI: 10.1016/j.exmath.2024.125602
Atul Dixit
In this expository article, we discuss the contributions made by several mathematicians with regard to a famous formula of Ramanujan for odd zeta values. The goal is to complement the excellent survey by Berndt and Straub (2017) with some of the recent developments that have taken place in the area in the last decade or so.
{"title":"Recent developments pertaining to Ramanujan’s formula for odd zeta values","authors":"Atul Dixit","doi":"10.1016/j.exmath.2024.125602","DOIUrl":"10.1016/j.exmath.2024.125602","url":null,"abstract":"<div><p>In this expository article, we discuss the contributions made by several mathematicians with regard to a famous formula of Ramanujan for odd zeta values. The goal is to complement the excellent survey by Berndt and Straub (2017) with some of the recent developments that have taken place in the area in the last decade or so.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 5","pages":"Article 125602"},"PeriodicalIF":0.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930613","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}
Pub Date : 2024-08-02DOI: 10.1016/j.exmath.2024.125601
Christian Berg
Let for . We prove that is a complete Bernstein function for and a Stieltjes function for . This answers a conjecture of David Bradley that is a Bernstein function when .
{"title":"A complete Bernstein function related to the fractal dimension of Pascal’s pyramid modulo a prime","authors":"Christian Berg","doi":"10.1016/j.exmath.2024.125601","DOIUrl":"https://doi.org/10.1016/j.exmath.2024.125601","url":null,"abstract":"Let for . We prove that is a complete Bernstein function for and a Stieltjes function for . This answers a conjecture of David Bradley that is a Bernstein function when .","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"56 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930603","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}
Pub Date : 2024-07-18DOI: 10.1016/j.exmath.2024.125591
Nuria Corral , Marcelo E. Hernandes , M.E. Rodrigues Hernandes
In this work we describe dicritical foliations in at a triple point of the resolution dual graph of an analytic plane branch using its semiroots. In particular, we obtain a constructive method to present a one-parameter family of separatrices for such foliations. As a by-product we relate the contact order between a special member of and with analytic discrete invariants of plane branches.
{"title":"Dicritical foliations and semiroots of plane branches","authors":"Nuria Corral , Marcelo E. Hernandes , M.E. Rodrigues Hernandes","doi":"10.1016/j.exmath.2024.125591","DOIUrl":"10.1016/j.exmath.2024.125591","url":null,"abstract":"<div><p>In this work we describe dicritical foliations in <span><math><mrow><mo>(</mo><msup><mrow><mi>ℂ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo><mn>0</mn><mo>)</mo></mrow></math></span> at a triple point of the resolution dual graph of an analytic plane branch <span><math><mi>C</mi></math></span> using its semiroots. In particular, we obtain a constructive method to present a one-parameter family <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span> of separatrices for such foliations. As a by-product we relate the contact order between a special member of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span> and <span><math><mi>C</mi></math></span> with analytic discrete invariants of plane branches.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 5","pages":"Article 125591"},"PeriodicalIF":0.8,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0723086924000586/pdfft?md5=3299d7524f5c5d739013dc887d4e9582&pid=1-s2.0-S0723086924000586-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-17DOI: 10.1016/j.exmath.2024.125592
Paolo Aniello, Sonia L’Innocente, Stefano Mancini, Vincenzo Parisi, Ilaria Svampa, Andreas Winter
We determine the Haar measure on the compact -adic special orthogonal groups of rotations in dimension , by exploiting the machinery of inverse limits of measure spaces, for every prime . We characterise the groups as inverse limits of finite groups, of which we provide parametrisations and orders, together with an equivalent description through a multivariable Hensel lifting. Supplying these finite groups with their normalised counting measures, we get an inverse family of Haar measure spaces for each . Finally, we constructively prove the existence of the so-called inverse limit measure of these inverse families, which is explicitly computable, and prove that it gives the Haar measure on . Our results pave the way towards the study of the irreducible projective unitary representations of the -adic rotation groups, with potential applications to the recently proposed -adic quantum information theory.
{"title":"Characterising the Haar measure on the [formula omitted]-adic rotation groups via inverse limits of measure spaces","authors":"Paolo Aniello, Sonia L’Innocente, Stefano Mancini, Vincenzo Parisi, Ilaria Svampa, Andreas Winter","doi":"10.1016/j.exmath.2024.125592","DOIUrl":"https://doi.org/10.1016/j.exmath.2024.125592","url":null,"abstract":"We determine the Haar measure on the compact -adic special orthogonal groups of rotations in dimension , by exploiting the machinery of inverse limits of measure spaces, for every prime . We characterise the groups as inverse limits of finite groups, of which we provide parametrisations and orders, together with an equivalent description through a multivariable Hensel lifting. Supplying these finite groups with their normalised counting measures, we get an inverse family of Haar measure spaces for each . Finally, we constructively prove the existence of the so-called inverse limit measure of these inverse families, which is explicitly computable, and prove that it gives the Haar measure on . Our results pave the way towards the study of the irreducible projective unitary representations of the -adic rotation groups, with potential applications to the recently proposed -adic quantum information theory.","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"120 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880872","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}
Pub Date : 2024-07-16DOI: 10.1016/j.exmath.2024.125593
S. Marini , C. Medori , M. Nacinovich
We study the correspondence between equivalence classes of pairs consisting of real semisimple Lie algebras and their Cartan subalgebras and involutions of the corresponding root system. This can be graphically described by introducing - and -diagrams, generalizing those of Satake and Vogan.
{"title":"Root involutions, real forms and diagrams","authors":"S. Marini , C. Medori , M. Nacinovich","doi":"10.1016/j.exmath.2024.125593","DOIUrl":"10.1016/j.exmath.2024.125593","url":null,"abstract":"<div><p>We study the correspondence between equivalence classes of pairs consisting of real semisimple Lie algebras and their Cartan subalgebras and involutions of the corresponding root system. This can be graphically described by introducing <span><math><mrow><mi>S</mi><mspace></mspace></mrow></math></span>- and <span><math><mi>Σ</mi></math></span>-<em>diagrams</em>, generalizing those of Satake and Vogan.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 5","pages":"Article 125593"},"PeriodicalIF":0.8,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0723086924000604/pdfft?md5=445995afea316cbdb564083c3930d697&pid=1-s2.0-S0723086924000604-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141713250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-11DOI: 10.1016/j.exmath.2024.125590
J.M. García-Calcines
The concept of relative sectional category expands upon classical sectional category theory by incorporating the pullback of a fibration along a map. Our paper aims not only to explore this extension but also to thoroughly investigate its properties. We seek to uncover how the relative sectional category unifies several homotopic numerical invariants found in recent literature. These include the topological complexity of maps according to Murillo–Wu or Scott, relative topological complexity as defined by Farber, and homotopic distance for continuous maps in the sense of Macías-Virgós and Mosquera-Lois, among others.
{"title":"Relative sectional category revisited","authors":"J.M. García-Calcines","doi":"10.1016/j.exmath.2024.125590","DOIUrl":"10.1016/j.exmath.2024.125590","url":null,"abstract":"<div><p>The concept of relative sectional category expands upon classical sectional category theory by incorporating the pullback of a fibration along a map. Our paper aims not only to explore this extension but also to thoroughly investigate its properties. We seek to uncover how the relative sectional category unifies several homotopic numerical invariants found in recent literature. These include the topological complexity of maps according to Murillo–Wu or Scott, relative topological complexity as defined by Farber, and homotopic distance for continuous maps in the sense of Macías-Virgós and Mosquera-Lois, among others.</p></div>","PeriodicalId":50458,"journal":{"name":"Expositiones Mathematicae","volume":"42 5","pages":"Article 125590"},"PeriodicalIF":0.8,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0723086924000574/pdfft?md5=e497014632089ab2358c7bdb9c539959&pid=1-s2.0-S0723086924000574-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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