In geometry, Euler's rotation theorem states that, in three-dimensional space, any displacement of a rigid body such that a point on the body remains fixed, is equivalent to a single rotation about so
Figure 1: Blue great circle on sphere transforms into red great circle when rotated about diameter through O.
In mathematics, the quaternions form a number system similar to the complex numbers, with the usual arithmetical operations of addition, subtraction, multiplication, and division, but with four real-n
Quaternion plaque on Brougham (Broom) Bridge, Dublin, which reads: Here as he walked by on the 16th of October 1843 Sir William Rowan Hamilton in a flash of genius discovered the fundamental formula for quaternion multiplication i2 = j2 = k2 = i j k = −1 & cut it on a stone of this bridge