[grey_whiskers]

Can you post a source for that?

Quaternions are our *friends*. :-)

Ive used them in dynamics problems to eliminate spurious ininfities in a term with sin(theta) in the denominator...

Cheers!

[Talisker]

Can you post a source for that?

Sure, it was from a three-part discussion of hyperdimensional physics by Richard Hoagland. The specific part involving quaternions were in a description of the reduction of Maxwell's equations, where there was no recognition of the energy potentials of scalar componants, versus that of vector componants, leading to the scalar componants being factored out in a "reduction" of the number of equations.

Hoagland's work is, as I am sure you are aware, the subject of a lot of argument over it's validity. Nevertheless I have found him to be a source of a lot of information that is otherwise refused acknowledgement. And he's been shown to be right more times than not, to the consternation of NASA.

Anyway, if it's your cup of tea, Cheers!

http://www.enterprisemission.com/hyper1.html

http://www.enterprisemission.com/hyper1a.html

http://www.enterprisemission.com/hyper2.html

http://www.enterprisemission.com/hyper2a.html

http://www.enterprisemission.com/hyper3.html