Results 41 to 50 of about 19,319 (303)

Roots of unity in definite quaternion orders

open access: yes, 2014
A commutative order in a quaternion algebra is called selective if it is embeds into some, but not all, the maximal orders in the algebra. It is known that a given quadratic order over a number field can be selective in at most one indefinite quaternion ...
Arenas-Carmona, Luis
core   +2 more sources

Quaternion-Based Two-Dimensional DOA Estimation for Coherent Underwater Sources Without Eigendecomposition

open access: yesIEEE Access, 2021
For scenarios of coherent underwater sources at low signal-to-noise ratio (SNR), a novel quaternion-based DOA algorithm without eigendecomposition is proposed using a linear vector-hydrophone array.
Yi Lou   +3 more
doaj   +1 more source

Convolution Theorems for Quaternion Fourier Transform: Properties and Applications

open access: yesAbstract and Applied Analysis, 2013
General convolution theorems for two-dimensional quaternion Fourier transforms (QFTs) are presented. It is shown that these theorems are valid not only for real-valued functions but also for quaternion-valued functions. We describe some useful properties
Mawardi Bahri   +2 more
doaj   +1 more source

Quaternions and the Algebra of Vectors [PDF]

open access: yesNature, 1891
MY remark about Prof. Willard Gibbs was meant in all courtesy, and I am happy to find it so taken by him. The question between us, being thus a scientific one only, can afford to wait for a fortnight or so:—until my present examination reason is past.
openaire   +2 more sources

Splitting of differential quaternion algebras

open access: yesJournal of Algebra, 2023
We study differential splitting fields of quaternion algebras with derivations. A quaternion algebra over a field $k$ is always split by a quadratic extension of $k$. However, a differential quaternion algebra need not be split over any algebraic extension of $k$.
Parul Gupta   +2 more
openaire   +2 more sources

Weighted Convolution for Quaternion Linear Canonical Cosine Transform and Its Application

open access: yesAxioms
Convolution plays a pivotal role in the domains of signal processing and optics. This paper primarily focuses on studying the weighted convolution for quaternion linear canonical cosine transform (QLCcT) and its application in multiplicative filter ...
Rongbo Wang, Qiang Feng
doaj   +1 more source

Asymptotic and Mittag–Leffler Synchronization of Fractional-Order Octonion-Valued Neural Networks with Neutral-Type and Mixed Delays

open access: yesFractal and Fractional, 2023
Very recently, a different generalization of real-valued neural networks (RVNNs) to multidimensional domains beside the complex-valued neural networks (CVNNs), quaternion-valued neural networks (QVNNs), and Clifford-valued neural networks (ClVNNs) has ...
Călin-Adrian Popa
doaj   +1 more source

Quaternion Algebras with the Same Subfields [PDF]

open access: yes, 2010
G. Prasad and A. Rapinchuk asked if two quaternion division F -algebras that have the same subfields are necessarily isomorphic. The answer is known to be "no" for some very large fields. We prove that the answer is "yes" if F is an extension of a global field K so that F /K is unirational and has zero unramified Brauer group.
Skip Garibaldi, David Saltman
openaire   +3 more sources

A Q‐Learning Algorithm to Solve the Two‐Player Zero‐Sum Game Problem for Nonlinear Systems

open access: yesInternational Journal of Adaptive Control and Signal Processing, Volume 39, Issue 3, Page 566-581, March 2025.
A Q‐learning algorithm to solve the two‐player zero‐sum game problem for nonlinear systems. ABSTRACT This paper deals with the two‐player zero‐sum game problem, which is a bounded L2$$ {L}_2 $$‐gain robust control problem. Finding an analytical solution to the complex Hamilton‐Jacobi‐Issacs (HJI) equation is a challenging task.
Afreen Islam   +2 more
wiley   +1 more source

Realizing algebraic invariants of hyperbolic surfaces

open access: yes, 2017
Let $S_g$ ($g\geq 2$) be a closed surface of genus $g$. Let $K$ be any real number field and $A$ be any quaternion algebra over $K$ such that $A\otimes_K\mathbb{R}\cong M_2(\mathbb{R})$. We show that there exists a hyperbolic structure on $S_g$ such that
Jeon, BoGwang
core   +1 more source

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