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Recently, graph neural networks (GNNs) have become an important and active research direction in deep learning. It is worth noting that most of the existing GNN-based methods learn graph representations within the Euclidean vector space.…

Machine Learning · Computer Science 2021-10-08 Dai Quoc Nguyen , Tu Dinh Nguyen , Dinh Phung

The fundamental properties of biquaternions (complexified quaternions) are presented including several different representations, some of them new, and definitions of fundamental operations such as the scalar and vector parts, conjugates,…

Rings and Algebras · Mathematics 2015-06-25 Stephen J. Sangwine , Todd A. Ell , Nicolas Le Bihan

Optimization models involving quaternion matrices are widely used in color image process and other engineering areas. These models optimize real functions of quaternion matrix variables. In particular, $\ell_0$-norms and rank functions of…

Optimization and Control · Mathematics 2020-11-10 Liqun Qi , Ziyan Luo , Qingwen Wang , Xinzhen Zhang

Recent works have demonstrated reasonable success of representation learning in hypercomplex space. Specifically, "fully-connected layers with Quaternions" (4D hypercomplex numbers), which replace real-valued matrix multiplications in…

Machine Learning · Computer Science 2021-02-18 Aston Zhang , Yi Tay , Shuai Zhang , Alvin Chan , Anh Tuan Luu , Siu Cheung Hui , Jie Fu

The field of neural networks has seen significant advances in recent years with the development of deep and convolutional neural networks. Although many of the current works address real-valued models, recent studies reveal that neural…

Computer Vision and Pattern Recognition · Computer Science 2021-12-14 Marco Aurélio Granero , Cristhian Xavier Hernández , Marcos Eduardo Valle

A split hypercomplex learning algorithm for the training of nonlinear finite impulse response adaptive filters for the processing of hypercomplex signals of any dimension is proposed. The derivation strictly takes into account the laws of…

Computer Vision and Pattern Recognition · Computer Science 2013-06-10 Eckhard Hitzer

Deep learning is a research hot topic in the field of machine learning. Real-value neural networks (Real NNs), especially deep real networks (DRNs), have been widely used in many research fields. In recent years, the deep complex networks…

Computer Vision and Pattern Recognition · Computer Science 2019-03-21 Jiasong Wu , Ling Xu , Youyong Kong , Lotfi Senhadji , Huazhong Shu

We show that the core reasons that complex and hypercomplex valued neural networks offer improvements over their real-valued counterparts is the weight sharing mechanism and treating multidimensional data as a single entity. Their algebra…

Neural and Evolutionary Computing · Computer Science 2020-09-10 Chase J Gaudet , Anthony S Maida

Linear algebra is usually defined over a field such as the reals or complex numbers. It is possible to extend this to skew fields such as the quaternions. However, to the authors' knowledge there is no commonly accepted notation of linear…

Rings and Algebras · Mathematics 2014-03-21 Dominik Schulz , Reiner S. Thomä

Deep learning for predicting or generating 3D human pose sequences is an active research area. Previous work regresses either joint rotations or joint positions. The former strategy is prone to error accumulation along the kinematic chain,…

Computer Vision and Pattern Recognition · Computer Science 2018-08-02 Dario Pavllo , David Grangier , Michael Auli

Since their first applications, Convolutional Neural Networks (CNNs) have solved problems that have advanced the state-of-the-art in several domains. CNNs represent information using real numbers. Despite encouraging results, theoretical…

Artificial Intelligence · Computer Science 2025-12-22 Gerardo Altamirano-Gomez , Carlos Gershenson

We give a simple and self contained introduction to quaternions and their practical usage in dynamics. The rigid body dynamics are presented in full details. In the appendix, some more exotic relations are given that allow to write more…

Dynamical Systems · Mathematics 2008-11-19 Basile Graf

We study matrix forms of quaternionic versions of the Fourier Transform and Convolution operations. Quaternions offer a powerful representation unit, however they are related to difficulties in their use that stem foremost from…

Computer Vision and Pattern Recognition · Computer Science 2024-07-23 Giorgos Sfikas , George Retsinas

Rotation representations are foundational in fields such as computer graphics, robotics, and machine learning, where precise and efficient modeling of 3D orientations is critical. This paper comprehensively investigates diverse…

Graphics · Computer Science 2026-05-12 Aizierjiang Aiersilan , Haochen Liu , James Hahn

This paper proposes a novel matrix rank-one decomposition for quaternion Hermitian matrices, which admits a stronger property than the previous results in (sturm2003cones,huang2007complex,ai2011new). The enhanced property can be used to…

Optimization and Control · Mathematics 2021-09-14 Chang He , Bo Jiang , Xihua Zhu

Rotations on the 3-dimensional Euclidean vector-space can be represented by real quaternions, as was shown by Hamilton. Introducing complex quaternions allows us to extend the result to elliptic and hyperbolic rotations on the Minkowski…

Optics · Physics 2024-07-17 Pierre Pellat-Finet

Multidimensional quaternion arrays (often referred to as "quaternion tensors") and their decompositions have recently gained increasing attention in various fields such as color and polarimetric imaging or video processing. Despite this…

Numerical Analysis · Mathematics 2025-10-13 Julien Flamant , Xavier Luciani , Sebastian Miron , Yassine Zniyed

A novel framework for a unifying treatment of quaternion valued adaptive filtering algorithms is introduced. This is achieved based on a rigorous account of quaternion differentiability, the proposed I-gradient, and the use of augmented…

General Mathematics · Mathematics 2013-10-22 Cyrus Jahanchahi , Danilo P. Mandic

We propose a novel quaternion product unit (QPU) to represent data on 3D rotation groups. The QPU leverages quaternion algebra and the law of 3D rotation group, representing 3D rotation data as quaternions and merging them via a weighted…

Computer Vision and Pattern Recognition · Computer Science 2020-04-03 Xuan Zhang , Shaofei Qin , Yi Xu , Hongteng Xu

In this article, we give the most genaral form of the quaternions algebra depending on 3-parameters. We define 3-parameter generalized quaternions (3PGQs) and study on various properties and applications. Firstly we present the definiton,…

Algebraic Geometry · Mathematics 2021-01-29 Tuncay Deniz Şentürk , Zafer Ünal