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 _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
