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Keywords = Cayley transformation

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46 pages, 17580 KB  
Article
Joint Hyperspectral Images and LiDAR Data Classification Combined with Quantum-Inspired Entangled Mamba
by Davaajargal Myagmarsuren, Aili Wang, Haoran Lv, Haibin Wu, Gabor Molnar and Liang Yu
Remote Sens. 2025, 17(24), 4065; https://doi.org/10.3390/rs17244065 - 18 Dec 2025
Viewed by 1163
Abstract
The multimodal fusion of hyperspectral images (HSI) and LiDAR data for land cover classification encounters difficulties in modeling heterogeneous data characteristics and cross-modal dependencies, leading to the loss of complementary information due to concatenation, the inadequacy of fixed fusion weights to adapt to [...] Read more.
The multimodal fusion of hyperspectral images (HSI) and LiDAR data for land cover classification encounters difficulties in modeling heterogeneous data characteristics and cross-modal dependencies, leading to the loss of complementary information due to concatenation, the inadequacy of fixed fusion weights to adapt to spatially varying reliability, and the assumptions of linear separability for nonlinearly coupled patterns. We propose QIE-Mamba, integrating selective state-space models with quantum-inspired processing to enhance multimodal representation learning. The framework employs ConvNeXt encoders for hierarchical feature extraction, quantum superposition layers for complex-valued multimodal encoding with learned amplitude–phase relationships, unitary entanglement networks via skew-symmetric matrix parameterization (validated through Cayley transform and matrix exponential methods), quantum-enhanced Mamba blocks with adaptive decoherence, and confidence-weighted measurement for classification. Systematic three-phase sequential validation on Houston2013, Muufl, and Augsburg datasets achieves overall accuracies of 99.62%, 96.31%, and 96.30%. Theoretical validation confirms 35.87% mutual information improvement over classical fusion (6.9966 vs. 5.1493 bits), with ablation studies demonstrating quantum superposition contributes 82% of total performance gains. Phase information accounts for 99.6% of quantum state entropy, while gradient convergence analysis confirms training stability (zero mean/std gradient norms). The optimization framework reduces hyperparameter search complexity by 99.6% while maintaining state-of-the-art performance. These results establish quantum-inspired state-space models as effective architectures for multimodal remote sensing fusion, providing reproducible methodology for hyperspectral–LiDAR classification with linear computational complexity. Full article
(This article belongs to the Section AI Remote Sensing)
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15 pages, 909 KB  
Article
R-Matrix Theory in a Semiconductor Quantum Device: Weak Formulation and Current Conserving Approximations
by Ulrich Wulf and Jan Kučera
Solids 2025, 6(4), 63; https://doi.org/10.3390/solids6040063 - 10 Nov 2025
Viewed by 1043
Abstract
In a series of previous publications an R-matrix approach was developed to describe transport in N-pole quantum devices in the Landauer–Büttiker formalism. Central quantities in this formalism are the transmission coefficients occurring in coherent scattering functions ranging throughout the device. Here we develop [...] Read more.
In a series of previous publications an R-matrix approach was developed to describe transport in N-pole quantum devices in the Landauer–Büttiker formalism. Central quantities in this formalism are the transmission coefficients occurring in coherent scattering functions ranging throughout the device. Here we develop the weak formulation version of this approach. It allows to introduce systematically approximations that reduce the exact problem to suitable matrix equations that can be solved on the computer. As a major advantage of our method any approximation found in the weak formulation approach to the R-matrix is current conserving by construction. Here the essential step is the representation of the current S-matrix by a Cayley transform. Restricting us to the one-dimensional case we find that the R-matrix in weak formulation generates a real symmetric Cayley transform by construction. From general theory it follows immediately that the current is conserved. Full article
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19 pages, 356 KB  
Article
Parabolic and Linear Rotational Motions on Cones and Hyperboloids
by Harun Barış Çolakoğlu, Mehmet Duru and Ayşe Yılmaz Ceylan
Axioms 2025, 14(8), 612; https://doi.org/10.3390/axioms14080612 - 6 Aug 2025
Viewed by 903
Abstract
In this study, we consider the Lorentzian rotation about a lightlike axis. First, we introduce a geometric characterization for the rotation angle between two vectors that can overlap each other under a Lorentzian rotation about a lightlike axis. Then, we give a definition [...] Read more.
In this study, we consider the Lorentzian rotation about a lightlike axis. First, we introduce a geometric characterization for the rotation angle between two vectors that can overlap each other under a Lorentzian rotation about a lightlike axis. Then, we give a definition for the angle measurement between two spacelike vectors whose vector product is lightlike. Later, we generalize the Lorentzian rotation about a lightlike axis, and determine matrices of these transformations using the Cartan frame and the well-known Rodrigues formula, then using the Cayley map, and finally using the generalized split quaternions. We see that such transformations give parabolic rotational motions on general cones or general hyperboloids of one or two sheets, while they also give linear rotational motions on general hyperboloids of one sheet. Full article
(This article belongs to the Section Geometry and Topology)
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30 pages, 898 KB  
Article
Discrete-Time Asymptotic Tracking Control System for a Satellite with a Solar Panel
by Zbigniew Emirsajłow
Appl. Sci. 2025, 15(12), 6674; https://doi.org/10.3390/app15126674 - 13 Jun 2025
Viewed by 950
Abstract
The aim of this work is to develop a discrete-time control algorithm that allows the attitude angle of a satellite with an attached solar panel to track a prescribed periodically changing reference signal with zero asymptotic error. Using the concept of the general [...] Read more.
The aim of this work is to develop a discrete-time control algorithm that allows the attitude angle of a satellite with an attached solar panel to track a prescribed periodically changing reference signal with zero asymptotic error. Using the concept of the general regulation theory for the state space setup, combined with a time discretization procedure based on the Cayley–Tustin transformation, we derive an error feedback controller. In our control analysis, we prove and explore several system-theoretic properties that are preserved under this continuous-to-discrete time transformation. The obtained discrete-time controller is then applied as a digital control system, demonstrating zero asymptotic tracking error. The theoretical results are tested on a numerical example and computations are performed within the MATLAB R2024b environment, confirming the highly useful nature of the developed approach. The controller also shows some robustness with respect to parametric uncertainty in the satellite model. Full article
(This article belongs to the Section Robotics and Automation)
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16 pages, 272 KB  
Article
Elliptic and Hyperbolic Rotational Motions on General Hyperboloids
by Harun Barış Çolakoğlu and Mehmet Duru
Symmetry 2025, 17(6), 845; https://doi.org/10.3390/sym17060845 - 28 May 2025
Cited by 1 | Viewed by 1042
Abstract
This study proposes a new way to represent elliptic and hyperbolic motions on any general hyperboloids of one or two sheets using the famous Rodrigues, Cayley, and Householder transformations. These transformations are used within the generalized Minkowski 3-space which extends the usual Lorentzian [...] Read more.
This study proposes a new way to represent elliptic and hyperbolic motions on any general hyperboloids of one or two sheets using the famous Rodrigues, Cayley, and Householder transformations. These transformations are used within the generalized Minkowski 3-space which extends the usual Lorentzian geometry by introducing a generalized scalar product. The study is carried out by considering the unit sphere defined in this generalized space along with the use of three-dimensional generalized Lorentzian skew-symmetric matrices that naturally generate continuous rotational motions. The obtained results provide rotational motions on the sphere in Minkowski 3-space as well as elliptic and hyperbolic motions on general hyperboloids in Euclidean 3-space. A numerical example is provided for each of the explored rotation methods. Full article
(This article belongs to the Section Mathematics)
39 pages, 53809 KB  
Article
Mathematical Modeling and Recursive Algorithms for Constructing Complex Fractal Patterns
by Abror Shavkatovich Buriboev, Djamshid Sultanov, Zulaykho Ibrohimova and Heung Seok Jeon
Mathematics 2025, 13(4), 646; https://doi.org/10.3390/math13040646 - 16 Feb 2025
Cited by 4 | Viewed by 7898
Abstract
In this paper, we present mathematical geometric models and recursive algorithms to generate and design complex patterns using fractal structures. By applying analytical, iterative methods, iterative function systems (IFS), and L-systems to create geometric models of complicated fractals, we developed fractal construction models, [...] Read more.
In this paper, we present mathematical geometric models and recursive algorithms to generate and design complex patterns using fractal structures. By applying analytical, iterative methods, iterative function systems (IFS), and L-systems to create geometric models of complicated fractals, we developed fractal construction models, visualization tools, and fractal measurement approaches. We introduced a novel recursive fractal modeling (RFM) method designed to generate intricate fractal patterns with enhanced control over symmetry, scaling, and self-similarity. The RFM method builds upon traditional fractal generation techniques but introduces adaptive recursion and symmetry-preserving transformations to produce fractals with applications in domains such as medical imaging, textile design, and digital art. Our approach differs from existing methods like Barnsley’s IFS and Jacquin’s fractal coding by offering faster convergence, higher precision, and increased flexibility in pattern customization. We used the RFM method to create a mathematical model of fractal objects that allowed for the viewing of polygonal, Koch curves, Cayley trees, Serpin curves, Cantor set, star shapes, circulars, intersecting circles, and tree-shaped fractals. Using the proposed models, the fractal dimensions of these shapes were found, which made it possible to create complex fractal patterns using a wide variety of complicated geometric shapes. Moreover, we created a software tool that automates the visualization of fractal structures. This tool may be used for a variety of applications, including the ornamentation of building items, interior and exterior design, and pattern construction in the textile industry. Full article
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19 pages, 313 KB  
Article
A Closed Form of Higher-Order Cayley Transforms and Generalized Rodrigues Vectors Parameterization of Rigid Motion
by Daniel Condurache, Mihail Cojocari and Ioan-Adrian Ciureanu
Mathematics 2025, 13(1), 114; https://doi.org/10.3390/math13010114 - 30 Dec 2024
Cited by 1 | Viewed by 1776
Abstract
This paper introduces a novel closed-form coordinate-free expression for the higher-order Cayley transform, a concept that has not been explored in depth before. The transform is defined by the Lie algebra of three-dimensional vectors into the Lie group of proper orthogonal Euclidean tensors. [...] Read more.
This paper introduces a novel closed-form coordinate-free expression for the higher-order Cayley transform, a concept that has not been explored in depth before. The transform is defined by the Lie algebra of three-dimensional vectors into the Lie group of proper orthogonal Euclidean tensors. The approach uses only elementary algebraic calculations with Euclidean vectors and tensors. The analytical expressions are given by rational functions by the Euclidean norm of vector parameterization. The inverse of the higher-order Cayley map is a multi-valued function that recovers the higher-order Rodrigues vectors (the principal parameterization and their shadows). Using vector parameterizations of the Euler and higher-order Rodrigues vectors, we determine the instantaneous angular velocity (in space and body frame), kinematics equations, and tangent operator. The analytical expressions of the parameterized quantities are identical for both the principal vector and shadows parameterization, showcasing the novelty and potential of our research. Full article
(This article belongs to the Special Issue Geometric Methods in Contemporary Engineering)
24 pages, 356 KB  
Article
Set-Theoretical Solutions for the Yang–Baxter Equation in GE-Algebras: Applications to Quantum Spin Systems
by Ibrahim Senturk, Tahsin Oner, Abdullah Engin Çalık, Hüseyin Şirin, Metin Bilge and Neelamegarajan Rajesh
Axioms 2024, 13(12), 846; https://doi.org/10.3390/axioms13120846 - 2 Dec 2024
Cited by 2 | Viewed by 2167
Abstract
This manuscript presents set-theoretical solutions to the Yang–Baxter equation within the framework of GE-algebras by constructing mappings that satisfy the braid condition and exploring the algebraic properties of GE-algebras. Detailed proofs and the use of left and right translation operators are provided to [...] Read more.
This manuscript presents set-theoretical solutions to the Yang–Baxter equation within the framework of GE-algebras by constructing mappings that satisfy the braid condition and exploring the algebraic properties of GE-algebras. Detailed proofs and the use of left and right translation operators are provided to analyze these algebraic interactions, while an algorithm is introduced to automate the verification process, facilitating broader applications in quantum mechanics and mathematical physics. Additionally, the Yang–Baxter equation is applied to spin transformations in quantum mechanical spin-12 systems, with transformations like rotations and reflections modeled using GE-algebras. A Cayley table is used to represent the algebraic structure of these transformations, and the proposed algorithm ensures that these solutions are consistent with the Yang–Baxter equation, offering new insights into the role of GE-algebras in quantum spin systems. Full article
13 pages, 336 KB  
Article
Generalized Galilean Rotations
by Harun Barış Çolakoğlu, İskender Öztürk, Oğuzhan Çelik and Mustafa Özdemir
Symmetry 2024, 16(11), 1553; https://doi.org/10.3390/sym16111553 - 20 Nov 2024
Cited by 3 | Viewed by 1526
Abstract
In this article, we give rotational motions on any straight line or any parabola in a scalar product space. To achieve this goal, we first define the generalized Galilean scalar product and determine the generalized Galilean skew symmetric and orthogonal matrices. Then, using [...] Read more.
In this article, we give rotational motions on any straight line or any parabola in a scalar product space. To achieve this goal, we first define the generalized Galilean scalar product and determine the generalized Galilean skew symmetric and orthogonal matrices. Then, using the well-known Rodrigues, Cayley, and Householder maps, we produce the generalized Galilean rotation matrices. Finally, we show that these rotation matrices can also be used to determine parabolic rotational motion. Full article
(This article belongs to the Section Mathematics)
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17 pages, 491 KB  
Article
Quaternion and Biquaternion Representations of Proper and Improper Transformations in Non-Cartesian Reference Systems
by Andrzej Katrusiak and Hien Quy Le
Symmetry 2024, 16(10), 1366; https://doi.org/10.3390/sym16101366 - 14 Oct 2024
Viewed by 2349
Abstract
Quaternion and biquaternion symmetry transformations have been applied to non-Cartesian reference systems of direct and reciprocal crystal lattices. The transformations performed directly in the sets of crystal reference axes simplify the calculations, eliminate the need for orthogonalization, permit the use of crystallographic vectors [...] Read more.
Quaternion and biquaternion symmetry transformations have been applied to non-Cartesian reference systems of direct and reciprocal crystal lattices. The transformations performed directly in the sets of crystal reference axes simplify the calculations, eliminate the need for orthogonalization, permit the use of crystallographic vectors for defining the directions of rotations and perform the computations directly in the crystal coordinates. The applications of the general quaternion transformations are envisioned for physical, chemical, crystallographic and engineering applications. The general quaternion multiplication rules for any symmetry-unrestricted lattices have been derived for the triclinic crystallographic system and have been applied to the biquaternion representations of all point-group symmetry elements, including the crystallographic hexagonal system. Cayley multiplication matrices for point-groups, based on the biquaternion symbols of proper and improper symmetry elements, have been exemplified. Full article
(This article belongs to the Section Physics)
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16 pages, 906 KB  
Article
mKdV Equation on Time Scales: Darboux Transformation and N-Soliton Solutions
by Baojian Jin, Yong Fang and Xue Sang
Axioms 2024, 13(9), 578; https://doi.org/10.3390/axioms13090578 - 25 Aug 2024
Cited by 1 | Viewed by 2011
Abstract
In this paper, the spectral problem of the mKdV equation satisfying the compatibility condition on time scales is directly constructed. By using the zero-curvature equation on time scales, the mKdV equation on time scales is obtained. When xR and  [...] Read more.
In this paper, the spectral problem of the mKdV equation satisfying the compatibility condition on time scales is directly constructed. By using the zero-curvature equation on time scales, the mKdV equation on time scales is obtained. When xR and tR, the equation degenerates to the classical mKdV equation. Then, the single-soliton, two-soliton, and N-soliton solutions of the mKdV equation under the zero boundary condition on time scales are presented via employing the Darboux transformation (DT). Particularly, we obtain the corresponding single-soliton solutions expressed using the Cayley exponential function on four different time scales (RZ, q-discrete, C). Full article
(This article belongs to the Section Mathematical Physics)
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16 pages, 1764 KB  
Article
Controllability of Fractional Complex Networks
by Xionggai Bao, Weiyuan Ma and Xin Li
Fractal Fract. 2024, 8(1), 43; https://doi.org/10.3390/fractalfract8010043 - 11 Jan 2024
Cited by 8 | Viewed by 2467
Abstract
Controllability is a fundamental issue in the field of fractional complex network control, yet it has not received adequate attention in the past. This paper is dedicated to exploring the controllability of complex networks involving the Caputo fractional derivative. By utilizing the Cayley–Hamilton [...] Read more.
Controllability is a fundamental issue in the field of fractional complex network control, yet it has not received adequate attention in the past. This paper is dedicated to exploring the controllability of complex networks involving the Caputo fractional derivative. By utilizing the Cayley–Hamilton theorem and Laplace transformation, a concise proof is given to determine the controllability of linear fractional complex networks. Subsequently, leveraging the Schauder Fixed-Point theorem, controllability Gramian matrix, and fractional calculus theory, we derive controllability conditions for nonlinear fractional complex networks with a weighted adjacency matrix and Laplacian matrix, respectively. Finally, a numerical method for the controllability of fractional complex networks is obtained using Matlab (2021a)/Simulink (2021a). Three examples are provided to illustrate the theoretical results. Full article
(This article belongs to the Special Issue Fractional Order Controllers for Non-linear Systems)
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23 pages, 618 KB  
Article
A Minimal Parameterization of Rigid Body Displacement and Motion Using a Higher-Order Cayley Map by Dual Quaternions
by Daniel Condurache and Ionuț Popa
Symmetry 2023, 15(11), 2011; https://doi.org/10.3390/sym15112011 - 1 Nov 2023
Cited by 2 | Viewed by 2473
Abstract
The rigid body displacement mathematical model is a Lie group of the special Euclidean group SE (3). This article is about the Lie algebra se (3) group. The standard exponential map from se (3) onto SE (3) is a natural parameterization of these [...] Read more.
The rigid body displacement mathematical model is a Lie group of the special Euclidean group SE (3). This article is about the Lie algebra se (3) group. The standard exponential map from se (3) onto SE (3) is a natural parameterization of these displacements. In technical applications, a crucial problem is the vector minimal parameterization of manifold SE (3). This paper presents a unitary variant of a general class of such vector parameterizations. In recent years, dual algebra has become a comprehensive framework for analyzing and computing the characteristics of rigid-body movements and displacements. Based on higher-order fractional Cayley transforms for dual quaternions, higher-order Rodrigues dual vectors and multiple vectorial parameters (extended by rotational cases) were computed. For the rigid body movement description, a dual tangent operator (for any vectorial minimal parameterization) was computed. This paper presents a unitary method for the initial value problem of the dual kinematic equation. Full article
14 pages, 416 KB  
Article
The Darboux Transformation and N-Soliton Solutions of Gerdjikov–Ivanov Equation on a Time–Space Scale
by Huanhe Dong, Xiaoqian Huang, Yong Zhang, Mingshuo Liu and Yong Fang
Axioms 2021, 10(4), 294; https://doi.org/10.3390/axioms10040294 - 5 Nov 2021
Cited by 7 | Viewed by 2793
Abstract
The Gerdjikov–Ivanov (GI) equation is one type of derivative nonlinear Schrödinger equation used widely in quantum field theory, nonlinear optics, weakly nonlinear dispersion water waves and other fields. In this paper, the coupled GI equation on a time–space scale is deduced from Lax [...] Read more.
The Gerdjikov–Ivanov (GI) equation is one type of derivative nonlinear Schrödinger equation used widely in quantum field theory, nonlinear optics, weakly nonlinear dispersion water waves and other fields. In this paper, the coupled GI equation on a time–space scale is deduced from Lax pairs and the zero curvature equation on a time–space scale, which can be reduced to the classical and the semi-discrete GI equation by considering different time–space scales. Furthermore, the Darboux transformation (DT) of the GI equation on a time–space scale is constructed via a gauge transformation. Finally, N-soliton solutions of the GI equation are given through applying its DT, which are expressed by the Cayley exponential function. At the same time, one-solition solutions are obtained on three different time–space scales ( X = R, X = C and X = Kp ). Full article
(This article belongs to the Special Issue Nonlinear Dynamical Systems with Applications)
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13 pages, 288 KB  
Article
Semigroups of Terms, Tree Languages, Menger Algebra of n-Ary Functions and Their Embedding Theorems
by Thodsaporn Kumduang and Sorasak Leeratanavalee
Symmetry 2021, 13(4), 558; https://doi.org/10.3390/sym13040558 - 27 Mar 2021
Cited by 21 | Viewed by 3263
Abstract
The concepts of terms and tree languages are significant tools for the development of research works in both universal algebra and theoretical computer science. In this paper, we establish a strong connection between semigroups of terms and tree languages, which provides the tools [...] Read more.
The concepts of terms and tree languages are significant tools for the development of research works in both universal algebra and theoretical computer science. In this paper, we establish a strong connection between semigroups of terms and tree languages, which provides the tools for studying monomorphisms between terms and generalized hypersubstitutions. A novel concept of a seminearring of non-deterministic generalized hypersubstitutions is introduced and some interesting properties among subsets of its are provided. Furthermore, we prove that there are monomorphisms from the power diagonal semigroup of tree languages and the monoid of generalized hypersubstitutions to the power diagonal semigroup of non-deterministic generalized hypersubstitutions and the monoid of non-deterministic generalized hypersubstitutions, respectively. Finally, the representation of terms using the theory of n-ary functions is defined. We then present the Cayley’s theorem for Menger algebra of terms, which allows us to provide a concrete example via full transformation semigroups. Full article
(This article belongs to the Special Issue The Study of Lattice Theory and Universal Algebra)
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