[racket] OT: SU(2) and friends

On Fri, Apr 22, 2011 at 08:08:08PM +0100, Paul Ellis wrote:
> Many thanks for the continuing interest. 
> 
> As you say, the 2nd is closer to my level and more accessible to me.
> (The first is likely to take me rather longer to be able to tackle.)
> 
> Something  I came across in the late Pertti Lounesto's "Clifford
> Algebras and Spinors" (2e, 2001; ISBN 0-521-00551-5), which resembles
> your 2nd ref,  makes statements such as: 
> 
> "In general, a rotation in R^4 has two invariant planes which are
> completely orthogonal, in particular they have only one point in
> common." ( p. 83)

You can also find similar stuff in Manning's book, The Geometry of Four 
Dimensions.  I have it as a Dover paperback that I bought in the 
fifties or sixties, but nowadays it seems to be available as a free 
download:

http://www.archive.org/details/geometryoffourdi033495mbp

-- hendrik