Pub Date : 2024-10-26DOI: 10.1007/s00006-024-01361-8
Yuanyuan Han, Pan Lian
In this paper, we extend Fueter’s theorem in hypercomplex function theory to encompass a class of pseudoanalytic functions associated with the main Vekua equation. This class includes Duffin’s (mu )-regular functions as special cases, which correspond to the Yukawa equation. As the parameter (mu rightarrow 0), we recover the classical Fueter’s theorem.
{"title":"Fueter’s Theorem for One Class of Pseudoanalytic Functions","authors":"Yuanyuan Han, Pan Lian","doi":"10.1007/s00006-024-01361-8","DOIUrl":"10.1007/s00006-024-01361-8","url":null,"abstract":"<div><p>In this paper, we extend Fueter’s theorem in hypercomplex function theory to encompass a class of pseudoanalytic functions associated with the main Vekua equation. This class includes Duffin’s <span>(mu )</span>-regular functions as special cases, which correspond to the Yukawa equation. As the parameter <span>(mu rightarrow 0)</span>, we recover the classical Fueter’s theorem.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142490663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1007/s00006-024-01357-4
André L. G. Mandolesi
We reorganize, simplify and expand the theory of contractions or interior products of multivectors, and related topics like Hodge star duality. Many results are generalized and new ones are given, like: geometric characterizations of blade contractions and regressive products, higher-order graded Leibniz rules, determinant formulas, improved complex star operators, etc. Different contractions found in the literature are discussed and compared, in special those of Clifford Geometric Algebra. Applications of the theory are developed in a follow-up paper.
{"title":"Multivector Contractions Revisited, Part I","authors":"André L. G. Mandolesi","doi":"10.1007/s00006-024-01357-4","DOIUrl":"10.1007/s00006-024-01357-4","url":null,"abstract":"<div><p>We reorganize, simplify and expand the theory of contractions or interior products of multivectors, and related topics like Hodge star duality. Many results are generalized and new ones are given, like: geometric characterizations of blade contractions and regressive products, higher-order graded Leibniz rules, determinant formulas, improved complex star operators, etc. Different contractions found in the literature are discussed and compared, in special those of Clifford Geometric Algebra. Applications of the theory are developed in a follow-up paper.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142488420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1007/s00006-024-01359-2
Haiyan Wang, Wei Xia
The Plemelj-Sokhotski formulas, which deal with limiting values of the Bochner-Martinelli type integral, are powerful tools for analyzing boundary value problems. This article aims to study the boundary behavior of the Bochner-Martinelli type integral formula for the k-Cauchy-Fueter operator. Specifically, we consider the Plemelj-Sokhotski formulas, which will extend the corresponding results in the complex analysis of several variables.
{"title":"The Plemelj-Sokhotski Formulas Associated to the k-Cauchy-Fueter Operator","authors":"Haiyan Wang, Wei Xia","doi":"10.1007/s00006-024-01359-2","DOIUrl":"10.1007/s00006-024-01359-2","url":null,"abstract":"<div><p>The Plemelj-Sokhotski formulas, which deal with limiting values of the Bochner-Martinelli type integral, are powerful tools for analyzing boundary value problems. This article aims to study the boundary behavior of the Bochner-Martinelli type integral formula for the <i>k</i>-Cauchy-Fueter operator. Specifically, we consider the Plemelj-Sokhotski formulas, which will extend the corresponding results in the complex analysis of several variables.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142453051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1007/s00006-024-01358-3
André L. G. Mandolesi
The theory of contractions of multivectors, and star duality, was reorganized in a previous article, and here we present some applications. First, we study inner and outer spaces associated to a general multivector M via the equations (v wedge M = 0) and (v mathbin {lrcorner }M=0). They are then used to analyze special decompositions, factorizations and ‘carvings’ of M, to define generalized grades, and to obtain new simplicity criteria, including a reduced set of Plücker-like relations. We also discuss how contractions are related to supersymmetry, and give formulas for supercommutators of multi-fermion creation and annihilation operators.
上一篇文章重新整理了多向量的收缩和星对偶理论,这里我们介绍一些应用。首先,我们通过方程 (v wedge M = 0)和 (v mathbin {lrcorner }M=0)来研究与一般多向量 M 相关的内部和外部空间。然后,我们用它们来分析 M 的特殊分解、因式分解和 "雕刻",定义广义等级,并得到新的简单性标准,包括一套简化的类似普吕克的关系。我们还讨论了收缩与超对称性的关系,并给出了多费米子创造和湮灭算子的超级互调器公式。
{"title":"Multivector Contractions Revisited, Part II","authors":"André L. G. Mandolesi","doi":"10.1007/s00006-024-01358-3","DOIUrl":"10.1007/s00006-024-01358-3","url":null,"abstract":"<div><p>The theory of contractions of multivectors, and star duality, was reorganized in a previous article, and here we present some applications. First, we study inner and outer spaces associated to a general multivector <i>M</i> via the equations <span>(v wedge M = 0)</span> and <span>(v mathbin {lrcorner }M=0)</span>. They are then used to analyze special decompositions, factorizations and ‘carvings’ of <i>M</i>, to define generalized grades, and to obtain new simplicity criteria, including a reduced set of Plücker-like relations. We also discuss how contractions are related to supersymmetry, and give formulas for supercommutators of multi-fermion creation and annihilation operators.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1007/s00006-024-01347-6
Daniel Alpay, Ilwoo Cho, Mihaela Vajiac
In this paper we describe the rise of global operators in the scaled quaternionic case, an important extension from the quaternionic case to the family of scaled hypercomplex numbers (mathbb {H}_t,, tin mathbb {R}^*), of which the (mathbb {H}_{-1}=mathbb {H}) is the space of quaternions and (mathbb {H}_{1}) is the space of split quaternions. We also describe the scaled Fueter-type variables associated to these operators, developing a coherent theory in this field. We use these types of variables to build different types of function spaces on (mathbb {H}_t). Counterparts of the Hardy space and of the Arveson space are also introduced and studied in the present setting. The two different adjoints in the scaled hypercomplex numbers lead to two parallel cases in each instance. Finally we introduce and study the notion of rational function.
{"title":"Scaled Global Operators and Fueter Variables on Non-zero Scaled Hypercomplex Numbers","authors":"Daniel Alpay, Ilwoo Cho, Mihaela Vajiac","doi":"10.1007/s00006-024-01347-6","DOIUrl":"10.1007/s00006-024-01347-6","url":null,"abstract":"<div><p>In this paper we describe the rise of global operators in the scaled quaternionic case, an important extension from the quaternionic case to the family of scaled hypercomplex numbers <span>(mathbb {H}_t,, tin mathbb {R}^*)</span>, of which the <span>(mathbb {H}_{-1}=mathbb {H})</span> is the space of quaternions and <span>(mathbb {H}_{1})</span> is the space of split quaternions. We also describe the scaled Fueter-type variables associated to these operators, developing a coherent theory in this field. We use these types of variables to build different types of function spaces on <span>(mathbb {H}_t)</span>. Counterparts of the Hardy space and of the Arveson space are also introduced and studied in the present setting. The two different adjoints in the scaled hypercomplex numbers lead to two parallel cases in each instance. Finally we introduce and study the notion of rational function.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00006-024-01347-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-12DOI: 10.1007/s00006-024-01360-9
Qianqian Kang, Guangzhen Ren, Yun Shi
The right-type groups are nilpotent Lie groups of step two having a pair of anticommutative operators, and many aspects of quaternionic analysis can be generalized to this kind of groups. In this paper, we use the twistor transformation to study the tangential k-Cauchy–Fueter equations and quaternionic k-regular functions on these groups. We introduce the twistor space over the ((4n+r))-dimensional complex right-type groups and use twistor transformation to construct an explicit Radon–Penrose type integral formula to solve the holomorphic tangential k-Cauchy–Fueter equation on these groups. When restricted to the real right-type group, this formula provides solutions to tangential k-Cauchy–Fueter equations. In particular, it gives us many k-regular polynomials.
右型群是具有一对反交换算子的二阶零势列群,四元数分析的许多方面都可以推广到这类群上。在本文中,我们利用扭转变换来研究这些群上的切向 k-Cauchy-Fueter 方程和四元数 k 正则函数。我们引入了在((4n+r))维复右型群上的扭转空间,并利用扭转变换构造了一个显式的 Radon-Penrose 型积分公式来求解这些群上的全纯切向 k-Cauchy-Fueter 方程。当局限于实右旋群时,该公式提供了切向 k-Cauchy-Fueter 方程的解。特别是,它给出了许多 k 正多项式。
{"title":"The Radon–Penrose Transformation for Quaternionic k-Regular Functions on Right-Type Groups","authors":"Qianqian Kang, Guangzhen Ren, Yun Shi","doi":"10.1007/s00006-024-01360-9","DOIUrl":"10.1007/s00006-024-01360-9","url":null,"abstract":"<div><p>The right-type groups are nilpotent Lie groups of step two having a pair of anticommutative operators, and many aspects of quaternionic analysis can be generalized to this kind of groups. In this paper, we use the twistor transformation to study the tangential <i>k</i>-Cauchy–Fueter equations and quaternionic <i>k</i>-regular functions on these groups. We introduce the twistor space over the <span>((4n+r))</span>-dimensional complex right-type groups and use twistor transformation to construct an explicit Radon–Penrose type integral formula to solve the holomorphic tangential <i>k</i>-Cauchy–Fueter equation on these groups. When restricted to the real right-type group, this formula provides solutions to tangential <i>k</i>-Cauchy–Fueter equations. In particular, it gives us many <i>k</i>-regular polynomials.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142411507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-27DOI: 10.1007/s00006-024-01348-5
Kai-Wen Si, Qing-Wen Wang, Lv-Ming Xie
We design several real representations of split quaternion matrices with the primary objective of establishing both necessary and sufficient conditions for the existence of solutions within a system of split quaternion matrix equations. This includes conditions for the general solution without any constraints, as well as (X=pm X^{eta }) solutions and (eta )-(anti-)Hermitian solutions. Furthermore, we derive the expressions for the general solutions when it is solvable. As an application, we investigate the solutions to a system of five split quaternion matrix equations involving (X^star ). Finally, we present several algorithms and numerical examples to demonstrate the results of this paper.
{"title":"A Classical System of Matrix Equations Over the Split Quaternion Algebra","authors":"Kai-Wen Si, Qing-Wen Wang, Lv-Ming Xie","doi":"10.1007/s00006-024-01348-5","DOIUrl":"10.1007/s00006-024-01348-5","url":null,"abstract":"<div><p>We design several real representations of split quaternion matrices with the primary objective of establishing both necessary and sufficient conditions for the existence of solutions within a system of split quaternion matrix equations. This includes conditions for the general solution without any constraints, as well as <span>(X=pm X^{eta })</span> solutions and <span>(eta )</span>-(anti-)Hermitian solutions. Furthermore, we derive the expressions for the general solutions when it is solvable. As an application, we investigate the solutions to a system of five split quaternion matrix equations involving <span>(X^star )</span>. Finally, we present several algorithms and numerical examples to demonstrate the results of this paper.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142325447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1007/s00006-024-01345-8
Ekaterina Filimoshina, Dmitry Shirokov
This paper investigates centralizers and twisted centralizers in degenerate and non-degenerate Clifford (geometric) algebras. We provide an explicit form of the centralizers and twisted centralizers of the subspaces of fixed grades, subspaces determined by the grade involution and the reversion, and their direct sums. The results can be useful for applications of Clifford algebras in computer science, physics, and engineering.
{"title":"A Note on Centralizers and Twisted Centralizers in Clifford Algebras","authors":"Ekaterina Filimoshina, Dmitry Shirokov","doi":"10.1007/s00006-024-01345-8","DOIUrl":"10.1007/s00006-024-01345-8","url":null,"abstract":"<div><p>This paper investigates centralizers and twisted centralizers in degenerate and non-degenerate Clifford (geometric) algebras. We provide an explicit form of the centralizers and twisted centralizers of the subspaces of fixed grades, subspaces determined by the grade involution and the reversion, and their direct sums. The results can be useful for applications of Clifford algebras in computer science, physics, and engineering.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1007/s00006-024-01349-4
Alexei Lisitsa, Mateo Salles, Alexei Vernitski
We use machine learning to classify examples of braids (or flat braids) as trivial or non-trivial. Our machine learning takes the form of supervised learning, specifically multilayer perceptron neural networks. When they achieve good results in classification, we are able to interpret their structure as mathematical conjectures and then prove these conjectures as theorems. As a result, we find new invariants of braids and prove several theorems related to them. This work evolves from our experiments exploring how different types of AI cope with untangling braids with 3 strands, this is why we concentrate mostly on braids with 3 strands.
{"title":"Machine Learning Discovers Invariants of Braids and Flat Braids","authors":"Alexei Lisitsa, Mateo Salles, Alexei Vernitski","doi":"10.1007/s00006-024-01349-4","DOIUrl":"10.1007/s00006-024-01349-4","url":null,"abstract":"<div><p>We use machine learning to classify examples of braids (or flat braids) as trivial or non-trivial. Our machine learning takes the form of supervised learning, specifically multilayer perceptron neural networks. When they achieve good results in classification, we are able to interpret their structure as mathematical conjectures and then prove these conjectures as theorems. As a result, we find new invariants of braids and prove several theorems related to them. This work evolves from our experiments exploring how different types of AI cope with untangling braids with 3 strands, this is why we concentrate mostly on braids with 3 strands.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00006-024-01349-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1007/s00006-024-01354-7
Jacques Helmstetter
This article has two purposes. After a short reminder of classical properties of meson algebras (also called Duffin-Kemmer algebras), Sects. 4 to 7 present recent advances in the study of their algebraic structure. Then Sects. 8 to 11 explain that each meson algebra contains a Lipschitz monoid with properties quite similar to those of Lipschitz monoids in Clifford algebras.
{"title":"Recent Advances for Meson Algebras and their Lipschitz Monoids","authors":"Jacques Helmstetter","doi":"10.1007/s00006-024-01354-7","DOIUrl":"10.1007/s00006-024-01354-7","url":null,"abstract":"<div><p>This article has two purposes. After a short reminder of classical properties of meson algebras (also called Duffin-Kemmer algebras), Sects. 4 to 7 present recent advances in the study of their algebraic structure. Then Sects. 8 to 11 explain that each meson algebra contains a Lipschitz monoid with properties quite similar to those of Lipschitz monoids in Clifford algebras.</p></div>","PeriodicalId":7330,"journal":{"name":"Advances in Applied Clifford Algebras","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00006-024-01354-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}