https://zh.wikipedia.org/wiki/四元数
从明确地角度而言,四元数是复数的不可交换延伸。如把四元数的集合考虑成多维实数空间的话,四元数就代表着一个四维空间,相对于复数为二维空间。
作为用于描述现实空间的坐标表示方式,人们在复数的基础上创造了四元数并以a+bi+cj+dk的形式说明空间点所在位置。 i、j、k作为一种特殊的虚数单位参与运算,并有以下运算规则:i0=j0=k0=1,i2=j2=k2=-1
对于i、j、k本身的几何意义可以理解为一种旋转,其中i旋转代表X轴与Y轴相交平面中X轴正向向Y轴正向的旋转,j旋转代表Z轴与X轴相交平面中Z轴正向向X轴正向的旋转,k旋转代表Y轴与Z轴相交平面中Y轴正向向Z轴正向的旋转,-i、-j、-k分别代表i、j、k旋转的反向旋转。
https://en.wikipedia.org/wiki/Quaternion
Quaternions find uses in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations such as in three-dimensional computer graphics, computer vision and crystallographic texture analysis.[5] In practical applications, they can be used alongside other methods, such as Euler angles and rotation matrices, or as an alternative to them, depending on the application.
http://mathworld.wolfram.com/Quaternion.html
The quaternions can be represented using complex matrices