Pub Date : 2025-03-24DOI: 10.1016/j.indag.2025.03.006
Shigeki Akiyama , Yuichi Kamiya , Fan Wen
Let us fold a strip of paper many times in the same direction, and then unfold it to form a fixed angle at all creases. The resulting shape is called the Dragon curve with the unfolding angle . When , the corresponding Dragon curve has a self-intersection. When , the corresponding Dragon curve is a straight line, which has no self-intersection. In this paper, we will show that any Dragon curve whose unfolding angle is greater than and less than has no self-intersection.
{"title":"Non-self-intersective Dragon curves","authors":"Shigeki Akiyama , Yuichi Kamiya , Fan Wen","doi":"10.1016/j.indag.2025.03.006","DOIUrl":"10.1016/j.indag.2025.03.006","url":null,"abstract":"<div><div>Let us fold a strip of paper many times in the same direction, and then unfold it to form a fixed angle <span><math><mi>θ</mi></math></span> at all creases. The resulting shape is called the Dragon curve with the unfolding angle <span><math><mi>θ</mi></math></span>. When <span><math><mrow><mn>0</mn><mo>≤</mo><mi>θ</mi><mo><</mo><mn>90</mn><mo>°</mo></mrow></math></span>, the corresponding Dragon curve has a self-intersection. When <span><math><mrow><mi>θ</mi><mo>=</mo><mn>180</mn><mo>°</mo></mrow></math></span>, the corresponding Dragon curve is a straight line, which has no self-intersection. In this paper, we will show that any Dragon curve whose unfolding angle is greater than <span><math><mrow><mn>99</mn><mo>.</mo><mn>3438</mn><mo>°</mo></mrow></math></span> and less than <span><math><mrow><mn>180</mn><mo>°</mo></mrow></math></span> has no self-intersection.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 5","pages":"Pages 1245-1275"},"PeriodicalIF":0.8,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895927","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 : 2025-03-13DOI: 10.1016/j.indag.2025.03.001
Joachim Schwermer
Using the quaternionic formalism for the description of the group of isometries of hyperbolic 5-space we consider arithmetically defined 5-dimensional hyperbolic manifolds which are non-compact but of finite volume. They arise from maximal orders in the central simple algebra of degree 4 where denotes a definite quaternion -algebra. The affine -group scheme determines an integral structure for the algebraic -group obtained by base change. The group is an inner form of the special linear -group . Each torsion-free subgroup determines a hyperbolic 5-manifold, to be denoted . Given a principal congruence subgroup , we determine the number of ends and the dimensions of the cohomology groups at infinity of the manifold .
{"title":"On arithmetically defined hyperbolic 5-manifolds arising from maximal orders in definite Q-algebras","authors":"Joachim Schwermer","doi":"10.1016/j.indag.2025.03.001","DOIUrl":"10.1016/j.indag.2025.03.001","url":null,"abstract":"<div><div>Using the quaternionic formalism for the description of the group of isometries of hyperbolic 5-space we consider arithmetically defined 5-dimensional hyperbolic manifolds which are non-compact but of finite volume. They arise from maximal orders <span><math><mi>Λ</mi></math></span> in the central simple algebra <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mi>D</mi><mo>)</mo></mrow></mrow></math></span> of degree 4 where <span><math><mi>D</mi></math></span> denotes a definite quaternion <span><math><mi>Q</mi></math></span>-algebra. The affine <span><math><mi>Z</mi></math></span>-group scheme <span><math><mrow><mi>S</mi><msub><mrow><mi>L</mi></mrow><mrow><mi>Λ</mi></mrow></msub></mrow></math></span> determines an integral structure for the algebraic <span><math><mi>Q</mi></math></span>-group <span><math><mrow><mi>G</mi><mo>=</mo><mi>S</mi><msub><mrow><mi>L</mi></mrow><mrow><mi>Λ</mi></mrow></msub><msub><mrow><mo>×</mo></mrow><mrow><mi>Z</mi></mrow></msub><mi>Q</mi></mrow></math></span> obtained by base change. The group <span><math><mi>G</mi></math></span> is an inner form of the special linear <span><math><mi>Q</mi></math></span>-group <span><math><mrow><mi>S</mi><msub><mrow><mi>L</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>. Each torsion-free subgroup <span><math><mrow><mi>Γ</mi><mo>⊂</mo><mi>S</mi><msub><mrow><mi>L</mi></mrow><mrow><mi>Λ</mi></mrow></msub><mrow><mo>(</mo><mi>Z</mi><mo>)</mo></mrow></mrow></math></span> determines a hyperbolic 5-manifold, to be denoted <span><math><mrow><msub><mrow><mi>X</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>/</mo><mi>Γ</mi></mrow></math></span>. Given a principal congruence subgroup <span><math><mrow><mi>Γ</mi><mrow><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>e</mi></mrow></msup><mo>)</mo></mrow></mrow></math></span>, we determine the number of ends and the dimensions of the cohomology groups at infinity of the manifold <span><math><mrow><msub><mrow><mi>X</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>/</mo><mi>Γ</mi><mrow><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>e</mi></mrow></msup><mo>)</mo></mrow></mrow></math></span>.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 5","pages":"Pages 1205-1222"},"PeriodicalIF":0.8,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896429","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 : 2025-03-11DOI: 10.1016/j.indag.2025.02.005
G. Bezhanishvili , F. Dashiell Jr. , M.A. Moshier , J. Walters-Wayland
We utilize the Bruns–Lakser completion to introduce Bruns–Lakser towers of a meet-semilattice. This machinery enables us to develop various hierarchies inside the class of bounded distributive lattices, which measure -degrees of distributivity of bounded distributive lattices and their Dedekind–MacNeille completions. We also use Priestley duality to obtain a dual characterization of the resulting hierarchies. Among other things, this yields a natural generalization of Esakia’s representation of Heyting lattices to proHeyting lattices.
{"title":"Degrees of join-distributivity via Bruns–Lakser towers","authors":"G. Bezhanishvili , F. Dashiell Jr. , M.A. Moshier , J. Walters-Wayland","doi":"10.1016/j.indag.2025.02.005","DOIUrl":"10.1016/j.indag.2025.02.005","url":null,"abstract":"<div><div>We utilize the Bruns–Lakser completion to introduce Bruns–Lakser towers of a meet-semilattice. This machinery enables us to develop various hierarchies inside the class of bounded distributive lattices, which measure <span><math><mi>κ</mi></math></span>-degrees of distributivity of bounded distributive lattices and their Dedekind–MacNeille completions. We also use Priestley duality to obtain a dual characterization of the resulting hierarchies. Among other things, this yields a natural generalization of Esakia’s representation of Heyting lattices to proHeyting lattices.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 5","pages":"Pages 1180-1204"},"PeriodicalIF":0.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896427","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 : 2025-03-07DOI: 10.1016/j.indag.2025.02.004
G.J. Heckman
This article has a twofold purpose. On the one hand I would like to draw attention to some nice exercises on the Kepler laws, due to Otto Laporte from 1970. Our discussion here has a more geometric flavor than the original analytic approach of Laporte.
On the other hand it serves as an addendum to a paper of mine from 1998 on the quantum integrability of the Kovalevsky top. Later I learned that this integrability result had been obtained already long before by Laporte in 1933.
{"title":"Exercises on the Kepler ellipses through a fixed point in space, after Otto Laporte","authors":"G.J. Heckman","doi":"10.1016/j.indag.2025.02.004","DOIUrl":"10.1016/j.indag.2025.02.004","url":null,"abstract":"<div><div>This article has a twofold purpose. On the one hand I would like to draw attention to some nice exercises on the Kepler laws, due to Otto Laporte from 1970. Our discussion here has a more geometric flavor than the original analytic approach of Laporte.</div><div>On the other hand it serves as an addendum to a paper of mine from 1998 on the quantum integrability of the Kovalevsky top. Later I learned that this integrability result had been obtained already long before by Laporte in 1933.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 6","pages":"Pages 1592-1599"},"PeriodicalIF":0.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374346","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 : 2025-02-25DOI: 10.1016/j.indag.2025.02.003
Pavel Etingof , Eric Rains
An important function attached to a complex simple Lie group is its asymptotic character (where are real (co)weights of ) – the Fourier transform in of its Duistermaat–Heckman function (continuous limit of weight multiplicities). It is shown in Garibaldi et al. that the best -independent upper bound for for fixed is strictly negative. We quantify this result by providing a lower bound for in terms of . We also provide upper and lower bounds for when . This allows us to show that for some constant depending only on , which implies the conjecture in Remark 17.16 of Garibaldi et al. We also show that . Finally, in the appendix we prove Conjecture 1 in Coquereaux and Zuber (2018) about Mittag-Leffler type sums for .
附在复单李群G上的一个重要函数是它的渐近特征X(λ, X)(其中λ, X是G的实(co)权)-它的Duistermaat-Heckman函数DHλ(p)(权复数的连续极限)在X中的傅里叶变换。Garibaldi等人证明,对于固定λ的infxReX(λ,x),最佳λ无关上界- c(G)是严格负的。我们通过用dimG给出c(G)的下界来量化这个结果。当|λ|=1时,我们还给出了DHλ(0)的上界和下界。这允许我们证明|X(λ, X)|≤C(G)|λ|−1| X |−1对于某常数C(G)只依赖于G,这暗示了Garibaldi等人在备注17.16中的猜想。我们还证明了c(SLn)≤(4π2)n−2。最后,在附录中,我们证明了Coquereaux和Zuber(2018)关于G的Mittag-Leffler型和的猜想1。
{"title":"Bounds for asymptotic characters of simple Lie groups","authors":"Pavel Etingof , Eric Rains","doi":"10.1016/j.indag.2025.02.003","DOIUrl":"10.1016/j.indag.2025.02.003","url":null,"abstract":"<div><div>An important function attached to a complex simple Lie group <span><math><mi>G</mi></math></span> is its asymptotic character <span><math><mrow><mi>X</mi><mrow><mo>(</mo><mi>λ</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> (where <span><math><mrow><mi>λ</mi><mo>,</mo><mi>x</mi></mrow></math></span> are real (co)weights of <span><math><mi>G</mi></math></span>) – the Fourier transform in <span><math><mi>x</mi></math></span> of its Duistermaat–Heckman function <span><math><mrow><mi>D</mi><msub><mrow><mi>H</mi></mrow><mrow><mi>λ</mi></mrow></msub><mrow><mo>(</mo><mi>p</mi><mo>)</mo></mrow></mrow></math></span> (continuous limit of weight multiplicities). It is shown in Garibaldi et al. that the best <span><math><mi>λ</mi></math></span>-independent upper bound <span><math><mrow><mo>−</mo><mi>c</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> for <span><math><mrow><msub><mrow><mo>inf</mo></mrow><mrow><mi>x</mi></mrow></msub><mi>Re</mi><mi>X</mi><mrow><mo>(</mo><mi>λ</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> for fixed <span><math><mi>λ</mi></math></span> is strictly negative. We quantify this result by providing a lower bound for <span><math><mrow><mi>c</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> in terms of <span><math><mrow><mo>dim</mo><mi>G</mi></mrow></math></span>. We also provide upper and lower bounds for <span><math><mrow><mi>D</mi><msub><mrow><mi>H</mi></mrow><mrow><mi>λ</mi></mrow></msub><mrow><mo>(</mo><mn>0</mn><mo>)</mo></mrow></mrow></math></span> when <span><math><mrow><mrow><mo>|</mo><mi>λ</mi><mo>|</mo></mrow><mo>=</mo><mn>1</mn></mrow></math></span>. This allows us to show that <span><math><mrow><mrow><mo>|</mo><mi>X</mi><mrow><mo>(</mo><mi>λ</mi><mo>,</mo><mi>x</mi><mo>)</mo></mrow><mo>|</mo></mrow><mo>≤</mo><mi>C</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><msup><mrow><mrow><mo>|</mo><mi>λ</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><msup><mrow><mrow><mo>|</mo><mi>x</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> for some constant <span><math><mrow><mi>C</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> depending only on <span><math><mi>G</mi></math></span>, which implies the conjecture in Remark 17.16 of Garibaldi et al. We also show that <span><math><mrow><mi>c</mi><mrow><mo>(</mo><mi>S</mi><msub><mrow><mi>L</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>)</mo></mrow><mo>≤</mo><msup><mrow><mrow><mo>(</mo><mfrac><mrow><mn>4</mn></mrow><mrow><msup><mrow><mi>π</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mo>)</mo></mrow></mrow><mrow><mi>n</mi><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>. Finally, in the appendix we prove Conjecture 1 in Coquereaux and Zuber (2018) about Mittag-Leffler type sums for <span><math><mi>G</mi></math></span>.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 6","pages":"Pages 1572-1591"},"PeriodicalIF":0.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374410","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 : 2025-02-11DOI: 10.1016/j.indag.2025.02.002
Nalini Joshi , Adri Olde Daalhuis
Usually when solving differential or difference equations via series solutions one encounters divergent series in which the coefficients grow like a factorial. Surprisingly, in the -world the th coefficient is often of the size , in which is fixed. Hence, the divergence is much stronger, and one has to introduce alternative Borel and Laplace transforms to make sense of these formal series. We will discuss exponentially-improved asymptotics for the basic hypergeometric function and for solutions of the -difference first Painlevé equation . These are optimal truncated expansions, and re-expansions in terms of new -hyperterminant functions. The re-expansions do incorporate the Stokes phenomena.
{"title":"Exponentially-improved asymptotics for q-difference equations: 2ϕ0 and qPI","authors":"Nalini Joshi , Adri Olde Daalhuis","doi":"10.1016/j.indag.2025.02.002","DOIUrl":"10.1016/j.indag.2025.02.002","url":null,"abstract":"<div><div>Usually when solving differential or difference equations via series solutions one encounters divergent series in which the coefficients grow like a factorial. Surprisingly, in the <span><math><mi>q</mi></math></span>-world the <span><math><mi>n</mi></math></span>th coefficient is often of the size <span><math><msup><mrow><mi>q</mi></mrow><mrow><mo>−</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mi>n</mi><mrow><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow></msup></math></span>, in which <span><math><mrow><mi>q</mi><mo>∈</mo><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>)</mo></mrow></mrow></math></span> is fixed. Hence, the divergence is much stronger, and one has to introduce alternative Borel and Laplace transforms to make sense of these formal series. We will discuss exponentially-improved asymptotics for the basic hypergeometric function <span><math><mrow><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>ϕ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span> and for solutions of the <span><math><mi>q</mi></math></span>-difference first Painlevé equation <span><math><mrow><mi>q</mi><msub><mrow><mi>P</mi></mrow><mrow><mi>I</mi></mrow></msub></mrow></math></span>. These are optimal truncated expansions, and re-expansions in terms of new <span><math><mi>q</mi></math></span>-hyperterminant functions. The re-expansions do incorporate the Stokes phenomena.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 6","pages":"Pages 1555-1571"},"PeriodicalIF":0.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374408","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 : 2025-02-11DOI: 10.1016/j.indag.2025.02.001
Paul Terwilliger
The -Onsager algebra is defined by two generators and two relations, called the -Dolan/Grady relations. In 2019, Baseilhac and Kolb introduced two automorphisms of , now called the Lusztig automorphisms. Recently, we introduced a generalization of called the -symmetric -Onsager algebra . The algebra has six distinguished generators, said to be standard. The standard -generators can be identified with the vertices of a regular hexagon, such that nonadjacent generators commute and adjacent generators satisfy the -Dolan/Grady relations. In the present paper we do the following: (i) for each standard -generator we construct an automorphism of called a Lusztig automorphism; (ii) we describe how the six Lusztig automorphisms of are related to each other; (iii) we describe what happens if a finite-dimensional irreducible -module is twisted by a Lusztig automorphism; (iv) we give a detailed example involving an irreducible -module with dimension 5.
{"title":"The S3-symmetric q-Onsager algebra and its Lusztig automorphisms","authors":"Paul Terwilliger","doi":"10.1016/j.indag.2025.02.001","DOIUrl":"10.1016/j.indag.2025.02.001","url":null,"abstract":"<div><div>The <span><math><mi>q</mi></math></span>-Onsager algebra <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> is defined by two generators and two relations, called the <span><math><mi>q</mi></math></span>-Dolan/Grady relations. In 2019, Baseilhac and Kolb introduced two automorphisms of <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>, now called the Lusztig automorphisms. Recently, we introduced a generalization of <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> called the <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>-symmetric <span><math><mi>q</mi></math></span>-Onsager algebra <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>. The algebra <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> has six distinguished generators, said to be standard. The standard <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>-generators can be identified with the vertices of a regular hexagon, such that nonadjacent generators commute and adjacent generators satisfy the <span><math><mi>q</mi></math></span>-Dolan/Grady relations. In the present paper we do the following: (i) for each standard <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>-generator we construct an automorphism of <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> called a Lusztig automorphism; (ii) we describe how the six Lusztig automorphisms of <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> are related to each other; (iii) we describe what happens if a finite-dimensional irreducible <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>-module is twisted by a Lusztig automorphism; (iv) we give a detailed example involving an irreducible <span><math><msub><mrow><mi>O</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>-module with dimension 5.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 6","pages":"Pages 1533-1554"},"PeriodicalIF":0.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374407","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 : 2025-02-07DOI: 10.1016/j.indag.2025.01.005
Étienne Fouvry , Peter Koymans
Given a binary quadratic form , we define its value set to be . If are two binary quadratic forms, we give necessary and sufficient conditions on and for .
{"title":"Binary quadratic forms with the same value set","authors":"Étienne Fouvry , Peter Koymans","doi":"10.1016/j.indag.2025.01.005","DOIUrl":"10.1016/j.indag.2025.01.005","url":null,"abstract":"<div><div>Given a binary quadratic form <span><math><mrow><mi>F</mi><mo>∈</mo><mi>Z</mi><mrow><mo>[</mo><mi>X</mi><mo>,</mo><mi>Y</mi><mo>]</mo></mrow></mrow></math></span>, we define its value set <span><math><mrow><mi>F</mi><mrow><mo>(</mo><msup><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow></math></span> to be <span><math><mrow><mo>{</mo><mi>F</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></mrow><mo>:</mo><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></mrow><mo>∈</mo><msup><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>}</mo></mrow></math></span>. If <span><math><mrow><mi>F</mi><mo>,</mo><mi>G</mi><mo>∈</mo><mi>Z</mi><mrow><mo>[</mo><mi>X</mi><mo>,</mo><mi>Y</mi><mo>]</mo></mrow></mrow></math></span> are two binary quadratic forms, we give necessary and sufficient conditions on <span><math><mi>F</mi></math></span> and <span><math><mi>G</mi></math></span> for <span><math><mrow><mi>F</mi><mrow><mo>(</mo><msup><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow><mo>=</mo><mi>G</mi><mrow><mo>(</mo><msup><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow></math></span>.</div></div>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 5","pages":"Pages 1157-1179"},"PeriodicalIF":0.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896426","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 : 2025-02-04DOI: 10.1016/j.indag.2025.01.006
Mabrouk Sghaier , Francisco Marcellán , Sabrine Hamdi
<div><div>Let <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span> be the Dunkl operator. A pair of symmetric measures <span><math><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></math></span> supported on a symmetric subset of the real line is said to be a symmetric Dunkl-coherent pair if the corresponding sequences of monic orthogonal polynomials <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> and <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> (resp.) satisfy <span><span><span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msub></mrow></mfrac><mo>−</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mfrac><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub></mrow></mfrac><mo>,</mo><mspace></mspace><mspace></mspace><mi>n</mi><mo>≥</mo><mn>2</mn><mo>,</mo></mrow></math></span></span></span>where <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>1</mn></mrow></msub></math></span><span> is a sequence of non-zero complex numbers and </span><span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mn>2</mn><mi>n</mi></mrow></msub><mo>=</mo><mn>2</mn><mi>n</mi><mo>,</mo><msub><mrow><mi>μ</mi></mrow><mrow><mn>2</mn><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mo>=</mo><mn>2</mn><mi>n</mi><mo>−</mo><mn>1</mn><mo>+</mo><mn>2</mn><mi>μ</mi><mo>,</mo><mi>n</mi><mo>≥</mo><mn>1</mn><mo>.</mo></mrow></math></span></div><div>In this contribution we focus the attention on the sequence <span><math><msub><mrow><mrow><mo>{</mo><msubsup><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow><mrow><mrow><mo>(</mo><mi>λ</mi><mo>,</mo><mi>μ</mi><mo>)</mo></mrow></mrow></msubsup><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> of monic orthogonal polynomials with respect to the Dunkl–Sobolev inner product <span><span><span><math><mrow><mo><</mo><mi>p</mi><mo>,</mo><mi>q</mi><msub><mrow><mo>></mo></mrow><mrow><mi>s</mi><mo>,</mo><mi>μ</mi></mrow></msub><mo>=</mo><mrow><mo>〈</mo><mi>u</mi><mo>,</mo><mi>p</mi>
{"title":"Dunkl symmetric coherent pairs of measures. An application to Fourier Dunkl–Sobolev expansions","authors":"Mabrouk Sghaier , Francisco Marcellán , Sabrine Hamdi","doi":"10.1016/j.indag.2025.01.006","DOIUrl":"10.1016/j.indag.2025.01.006","url":null,"abstract":"<div><div>Let <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span> be the Dunkl operator. A pair of symmetric measures <span><math><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></math></span> supported on a symmetric subset of the real line is said to be a symmetric Dunkl-coherent pair if the corresponding sequences of monic orthogonal polynomials <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> and <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> (resp.) satisfy <span><span><span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msub></mrow></mfrac><mo>−</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mfrac><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>P</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub></mrow></mfrac><mo>,</mo><mspace></mspace><mspace></mspace><mi>n</mi><mo>≥</mo><mn>2</mn><mo>,</mo></mrow></math></span></span></span>where <span><math><msub><mrow><mrow><mo>{</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>1</mn></mrow></msub></math></span><span> is a sequence of non-zero complex numbers and </span><span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mn>2</mn><mi>n</mi></mrow></msub><mo>=</mo><mn>2</mn><mi>n</mi><mo>,</mo><msub><mrow><mi>μ</mi></mrow><mrow><mn>2</mn><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msub><mo>=</mo><mn>2</mn><mi>n</mi><mo>−</mo><mn>1</mn><mo>+</mo><mn>2</mn><mi>μ</mi><mo>,</mo><mi>n</mi><mo>≥</mo><mn>1</mn><mo>.</mo></mrow></math></span></div><div>In this contribution we focus the attention on the sequence <span><math><msub><mrow><mrow><mo>{</mo><msubsup><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow><mrow><mrow><mo>(</mo><mi>λ</mi><mo>,</mo><mi>μ</mi><mo>)</mo></mrow></mrow></msubsup><mo>}</mo></mrow></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub></math></span> of monic orthogonal polynomials with respect to the Dunkl–Sobolev inner product <span><span><span><math><mrow><mo><</mo><mi>p</mi><mo>,</mo><mi>q</mi><msub><mrow><mo>></mo></mrow><mrow><mi>s</mi><mo>,</mo><mi>μ</mi></mrow></msub><mo>=</mo><mrow><mo>〈</mo><mi>u</mi><mo>,</mo><mi>p</mi>","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 6","pages":"Pages 1513-1532"},"PeriodicalIF":0.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145374406","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 : 2025-01-30DOI: 10.1016/j.indag.2025.01.003
Zhen Guo, Xin Li
<div><div>Suppose <span><math><mrow><mi>k</mi><mo>⩾</mo><mn>3</mn></mrow></math></span> is an integer. Let <span><math><mrow><msub><mrow><mi>τ</mi></mrow><mrow><mi>k</mi></mrow></msub><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> be the number of ways <span><math><mi>n</mi></math></span> can be written as a product of <span><math><mi>k</mi></math></span> fixed factors. For any fixed integer <span><math><mrow><mi>r</mi><mo>⩾</mo><mn>2</mn></mrow></math></span>, we have the asymptotic formula <span><span><span><math><mrow><munder><mrow><mo>∑</mo></mrow><mrow><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>⋯</mo><mspace></mspace><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>⩽</mo><mi>x</mi></mrow></munder><msub><mrow><mi>τ</mi></mrow><mrow><mi>k</mi></mrow></msub><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>⋯</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>)</mo></mrow><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>r</mi></mrow></msup><munderover><mrow><mo>∑</mo></mrow><mrow><mi>ℓ</mi><mo>=</mo><mn>0</mn></mrow><mrow><mi>r</mi><mrow><mo>(</mo><mi>k</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow></munderover><msub><mrow><mi>d</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi><mo>,</mo><mi>ℓ</mi></mrow></msub><msup><mrow><mrow><mo>(</mo><mo>log</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><mi>ℓ</mi></mrow></msup><mo>+</mo><mi>O</mi><mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>r</mi><mo>−</mo><mn>1</mn><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>k</mi></mrow></msub><mo>+</mo><mi>ɛ</mi></mrow></msup><mo>)</mo></mrow><mo>,</mo></mrow></math></span></span></span>where <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi><mo>,</mo><mi>ℓ</mi></mrow></msub></math></span> and <span><math><mrow><mn>0</mn><mo><</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>k</mi></mrow></msub><mo><</mo><mn>1</mn></mrow></math></span> are computable constants. In this paper we study the mean square of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> and give upper bounds for <span><math><mrow><mi>k</mi><mo>⩾</mo><mn>4</mn></mrow></math></span> and an asymptotic formula for the mean square of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span>. We also get an upper bound for the third power moment of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span>. Moreover, we study the first power moment of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> and then give a result for the sign
假设k大于或等于3是一个整数。设τk(n)是n可以写成k个固定因子的乘积的方法个数。对于任何固定整数r大于或等于2,我们有渐近公式∑n1,⋯nr≤xτk(n1⋯nr)=xr∑r =0r(k−1)dr,k, r(logx) r +O(xr−1+αk+ æ),其中dr,k, r和0<;αk<;1是可计算常数。在本文中,我们研究Δr,k(x)的均方并给出k小于或等于4的上限和Δr,3(x)的均方的渐近公式。我们也得到了Δr 3(x)的三次幂矩的上界。此外,我们还研究了Δr,3(x)的一阶幂矩,并给出了它的符号变化的结果。
{"title":"On moments of the error term of the multivariable kth divisor functions","authors":"Zhen Guo, Xin Li","doi":"10.1016/j.indag.2025.01.003","DOIUrl":"10.1016/j.indag.2025.01.003","url":null,"abstract":"<div><div>Suppose <span><math><mrow><mi>k</mi><mo>⩾</mo><mn>3</mn></mrow></math></span> is an integer. Let <span><math><mrow><msub><mrow><mi>τ</mi></mrow><mrow><mi>k</mi></mrow></msub><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> be the number of ways <span><math><mi>n</mi></math></span> can be written as a product of <span><math><mi>k</mi></math></span> fixed factors. For any fixed integer <span><math><mrow><mi>r</mi><mo>⩾</mo><mn>2</mn></mrow></math></span>, we have the asymptotic formula <span><span><span><math><mrow><munder><mrow><mo>∑</mo></mrow><mrow><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>⋯</mo><mspace></mspace><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>⩽</mo><mi>x</mi></mrow></munder><msub><mrow><mi>τ</mi></mrow><mrow><mi>k</mi></mrow></msub><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>⋯</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>)</mo></mrow><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>r</mi></mrow></msup><munderover><mrow><mo>∑</mo></mrow><mrow><mi>ℓ</mi><mo>=</mo><mn>0</mn></mrow><mrow><mi>r</mi><mrow><mo>(</mo><mi>k</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow></munderover><msub><mrow><mi>d</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi><mo>,</mo><mi>ℓ</mi></mrow></msub><msup><mrow><mrow><mo>(</mo><mo>log</mo><mi>x</mi><mo>)</mo></mrow></mrow><mrow><mi>ℓ</mi></mrow></msup><mo>+</mo><mi>O</mi><mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>r</mi><mo>−</mo><mn>1</mn><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>k</mi></mrow></msub><mo>+</mo><mi>ɛ</mi></mrow></msup><mo>)</mo></mrow><mo>,</mo></mrow></math></span></span></span>where <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi><mo>,</mo><mi>ℓ</mi></mrow></msub></math></span> and <span><math><mrow><mn>0</mn><mo><</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>k</mi></mrow></msub><mo><</mo><mn>1</mn></mrow></math></span> are computable constants. In this paper we study the mean square of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>k</mi></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> and give upper bounds for <span><math><mrow><mi>k</mi><mo>⩾</mo><mn>4</mn></mrow></math></span> and an asymptotic formula for the mean square of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span>. We also get an upper bound for the third power moment of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span>. Moreover, we study the first power moment of <span><math><mrow><msub><mrow><mi>Δ</mi></mrow><mrow><mi>r</mi><mo>,</mo><mn>3</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> and then give a result for the sign ","PeriodicalId":56126,"journal":{"name":"Indagationes Mathematicae-New Series","volume":"36 5","pages":"Pages 1133-1156"},"PeriodicalIF":0.8,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896428","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}