八元数矩阵的行列式及其性质

赋范的可除代数只有四种:实数R,复数C,四元数日和八元数O.由于八元数关于乘法非交换且非结合,如何对八元数矩阵定义行列式并使其具有较好的运算性质变得非常困难.最近,李兴民和黎丽根据"八元数自共轭矩阵的行列式应为实数"这一数学与物理上的需求,通过选择几个八元数乘积的次序和结合方式,首次给出了八元数行列式的定义.但是,与实数、复数以及四元数的相应的情形比较,如此定义的行列式,其所具备的运算性质较少.本文给出了一种新的八元数行列式的定义,它们具备了尽可能多的运算性质,同时使得"八元数自共轭矩阵的行列式为实数"不证自明.     

约化双四元数的代数性质

本文研究了约化双四元数的代数性质. 通过约化双四元数的实矩阵和复矩阵表示, 引入约化双四元数Moore-Penrose逆的概念. 作为应用,我们求解线性方程$ax=d$和二次方程$ax^2+bx+c=0$. 通过复表示,我们找到约化双四元数的$n$次根、$n$次幂和得到约化双四元数矩阵的指数函数的一些性质.     

四元数体上一类矩阵方程解的数值方法

建立了求解四元数体上严格对角占优矩阵方程AX=B的QJ和QSOR迭代方法,并利用四元数矩阵的右特征值最大模刻画出迭代的收敛性,给出参数的取值范围;最后运用四元数矩阵的复表示运算保结构的特性,把这两种迭代等价地转化到复数域上,从而实现了该系统的数值求解.     

Lorentz变换的四元数表示——纪念李国平院士吴新谋教授诞辰100周年

为一般Lorentz变换给出了一种新的形式简单的四元数表示. 其特点是所用四元数的分量要么是实数, 要么是纯虚数. 与以往的向量-张量表示和八元数表示(双四元数)相比, 有其明显的优点.     

Lorentz变换的四元数表示

为一般Lorentz变换给出了一种新的形式简单的四元数表示.其特点是所用四元数的分量要么是实数,要么是纯虚数.与以往的向量-张量表示和八元数表示(双四元数)相比,有其明显的优点.     

四元数自共轭矩阵乘积的特征值不等式

由于四元数对乘法无交换律,因而对四元数自共轭矩阵的特征值问题的讨论比复数矩阵的相应问题要困难得多,文[1]、[2]分别对四元数自共轭矩阵的特征值和两个四元数自共轭矩阵乘积的特征进行了估计,做了一定的工作,但与复数域上的有关结果相比较,还有较大差距.本文对四元数自共轭矩阵乘积的特征值进行了探讨.得到了较好的结论,推广了[1]、[2]中的结果。     

广义四元数的一次代数方程

本文运用广义四元数代数的矩阵表示讨论了两类广义四元数的一次代数方程的解问题，并得到了这两类代数方程有唯一解、无穷多解，无解的判别条件。     

复数

1　考点简析新课教学与高三备考复习是有区别的 .但是新课教学又不能不顾及高考 ,不能对高考的要求心中无数 ,而应当循序渐进地、有机地渗透“考试说明”的有关要求 .1.1　知识点剖析本章的知识点有 7个 (见课本 7个小节的标题 ) ,其内涵与外延是 :复数的有关概念 (含模与共轭复数的有关性质 ) ,复数的整体形式、代数形式、三角形式及其转换 ;复数代数式与三角式的运算 ,复数的几何表示 ,复数运算的几何意义 ,几何意义与运算的转换 ,图形与方程的转换 ;在复数集中解一元二次方程和二项方程 .1.2　思想方法化复 (数 )为实 (数 ) ,数形结合 ,…     

复数在几何中的应用

复数可以用点和向量表示,复数集与复平面上的点集及复平面上从坐标原点发出的向量集具有一一对应关系,复数的加减法运算可以按照向量的加减法进行,若设z=r(cosθ isinθ)复数z_1与向量OZ_1对应,那么Z·z_1的几何意义是把向量OZ_1绕o点按逆时针方向旋转θ角,再把|OZ_1|变为原来的r倍,而z-1/z(z≠0)的几何意义则是把向量OZ_1绕o点按顺时针方向转θ角,再把|OZ_1|变为原来的1/r倍,根据复数及其运算的几何意义,平面上某些图形的几何关系可以通过复数关系来刻划,从而一些几何问题就可以通过一系列的复数运算,巧妙地导出所需的结果。     

代数不等式的分拆降维方法与机器证明

利用双变元对称型所构成实线性空间的特点,设计了一种特殊形式的基,基中元素是非负的.如果一个元在此基下的坐标非负,则该元自身也是非负的.于是要证明某个元非负将被归结为证明其在指定基下的坐标非负.通常坐标中的变元数,少于原对称型的变元数,从而起到了降低维数的作用.对非对称型,可通过对称化转换为对称型来处理.根据该方法编制了Maple通用程序Bidecomp.虽此方法并非完备的,但大量的应用实例表明了此种方法证明多项式型不等式的有效性.     

A concise quaternion geometry of rotations

This communication compiles propositions concerning the spherical geometry of rotations when represented by unit quaternions. The propositions are thought to establish a two‐way correspondence between geometrical objects in the space of real unit quaternions representing rotations and geometrical objects constituted by directions in the three‐dimensional space subjected to these rotations. In this way a purely geometrical proof of the spherical Ásgeirsson's mean value theorem and a geometrical interpretation of integrals related to the spherical Radon transform of a probability density functions of unit quaternions are accomplished. Copyright © 2004 John Wiley & Sons, Ltd.     

On geometric interpretations of split quaternions

Quaternions are an important tool that provides a convenient and effective mathematical method for representing reflections and rotations in three-dimensional space. A unit timelike split quaternion represents a rotation in the Lorentzian space. In this paper, we give some geometric interpretations of split quaternions for lines and planes in the Minkowski 3-space with the help of mutual pseudo orthogonal planes. We classified mutual planes with respect to the casual character of the normals of the plane as follows; if the normal is timelike, then the mutual plane is isomorphic to the complex plane; if the normal is spacelike, then the plane is isomorphic to the hyperbolic number plane (Lorentzian plane); if the normal is lightlike, then the plane is isomorphic to the dual number plane (Galilean plane).     

Biquaternion (Complexified Quaternion) Roots of −1

The roots of −1 in the set of biquaternions (quaternions with complex components, or complex numbers with quaternion real and imaginary parts) are derived. There are trivial solutions (the complex operator, and any unit pure real quaternion), and non-trivial solutions consisting of complex numbers with perpendicular pure quaternion real and imaginary parts. The moduli of the two perpendicular pure quaternions are expressible by a single parameter by using a hyperbolic trigonometric identity.     

Numerical integration of rigid body dynamics in terms of quaternions

Unit–quaternions (or Euler parameter) are known to be well–suited for the singularity–free parametrization of finite rotations. Despite of this advantage, unit quaternions were rarely used to formulate the equations of motion (exceptions are the works by Nikravesh [1] and Haug [2]). This might be related to the fact, that the unit–quaternions are redundant, which requires the use of algebraic constraints in the equations of motion. Nowadays robust energy consistent integrators are available for the numerical solution of these differential–algebraic equations (DAEs). In the present work a mechanical integrator for the quaternions will be derived. This will be done by a size–reduction from the director formulation of the equations of motion, which also has the form of DAEs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Involutions in split semi‐quaternions

A map is an involution (resp, anti‐involution) if it is a self‐inverse homomorphism (resp, antihomomorphism) of a field algebra. The main purpose of this paper is to show how split semi‐quaternions can be used to express half‐turn planar rotations in 3‐dimensional Euclidean space and how they can be used to express hyperbolic‐isoclinic rotations in 4‐dimensional semi‐Euclidean space . We present an involution and an anti‐involution map using split semi‐quaternions and give their geometric interpretations as half‐turn planar rotations in . Also, we give the geometric interpretation of nonpure unit split semi‐quaternions, which are in the form p = coshθ + sinhθ i + 0 j + 0 k = coshθ + sinhθ i , as hyperbolic‐isoclinic rotations in .     

四元数中的真半范数

讨论了四元数中的真半范数，并给出了它的一般形式，它适合核维数分别为1，2，3的情形，推广了复数域中的真半范数的一般形式，给出了一个较好的结果．     

The Generalized Cauchy-Riemann-Fueter Equation and Handedness

A generalization of the Cauchy-Riemann condition in complex analysis is described for complex numbers, quaternions and complex quaternions. The generalization called here generalized Cauchy-Riemann-Fueter analycity encompasses not just the left and right-handed versions of quaternion analysis but also generates other variants for complex quaternions. These multiple variants are shown to satisfy an analogue of Cauchy's Theorem and to have similarities with the generalized Cauchy-Riemann conditions that define monogenic functions on R ^{n + 1}; they are also similar to Fueter-type operators and the Moisil-Theodoresco operator. The multiple variants are shown to have an interpretation that unifies analycity into a single definition. Thus left and right-handedness in quaternions are shown to be two sides of the same concept, and likewise for complex quaternions. This is then shown to have possible physical interpretation for example in understanding the nature of chirality and the 'arrow of time'.     

Quaternion Polar Representation with a Complex Modulus and Complex Argument Inspired by the Cayley-Dickson Form

We present a new polar representation of quaternions inspired by the Cayley-Dickson representation. In this new polar representation, a quaternion is represented by a pair of complex numbers as in the Cayley-Dickson form, but here these two complex numbers are a complex ‘modulus’ and a complex ‘argument’. As in the Cayley-Dickson form, the two complex numbers are in the same complex plane (using the same complex root of −1), but the complex phase is multiplied by a different complex root of −1 in the exponential function. We show how to calculate the ‘modulus’ and ‘argument’ from an arbitrary quaternion in Cartesian form.     

De Moivre''s formula for quaternions

Euler's formula and De Moivre's formula for complex numbers are generalized for quaternions. De Moivre's formula implies that there are uncountably many unit quaternions satisfying xⁿ = 1 for n ≥ 3.