This section is divided into a number of subsections, links to which are:
Cayley Representation
https://rotations.berkeley.edu/other-representations-of-a-rotation/1846, Cayley [17] introduced what is now known as the Cayley transform of a second-order skew-symmetric tensor A:
\begin{equation} \label{EqCayley.1}
\mbox{Cay}({\bf A}) = \left( {\bf I} - {\bf A} \right)^{-1} \left( {\bf I} + {\bf A} \right) .
\end{equation}
He showed that the Cayley transform of A = - AT is a proper-orthogonal tensor, and hence a rotation tensor1. The transform is often invertible. If C = Cay}(A = - AT), then
\begin{equation} \label{EqCayley.2}
{\bf A} = \left( {\bf C} - {\bf I} \right) \left( {\bf I} + {\bf C} \right)^{-1} ,
\end{equation}
provided I + C is invertible. It is interesting to note that
\[
\mbox{Cay}(-{\bf A}) = \left( \mbox{Cay}({\bf A}) \right)^{\mathrm T} .
\]
Thus, the inverse of a rotation is obtained by setting A ↦ - A. Given a skew-symmetric tensor Λ, we denote the representation defined by the Cayley transform of Λ as the Cayley representation of a rotation:
\begin{equation} \label{EqCayley.3}
{\bf R} = {\bf R}_{Cayley} \left( \Lambda \right) = \left( {\bf I} - \Lambda \right)^{-1} \left( {\bf I} + \Lambda \right) .
\end{equation}
- Cayley, A., Sur quelques propriétés des déterminants gauches, Journal für die reine und angewandte Mathematik 32 119-123 (1846). Reprinted in pp. 332-336 of The Collected Mathematical Papers of Arthur Cayley, Sc.D., F.R.S., Vol. 1, Cambridge University Press, Cambridge (1889).
- Mladenova, C. D., and Mladenov, I. M., Vector decomposition of finite rotations, Reports on Mathematical Physics 68(1) 107-117 (2011).
- Norris, A. N., >Euler-Rodrigues and Cayley formulae for rotation of elasticity tensors, Mathematics and Mechanics of Solids 13(6) 465-498 (2008).