Re: Digest Number 594

From: Hubert HOLIN (Hubert.Holin_at_[hidden])
Date: 2001-05-26 16:59:22

Paris (U.E.), le 26/05/2001

        Bonsoir!

--- In boost_at_y..., Peter Schmitteckert (boost) <boost_at_s...> wrote:
> Salut,
> 
> On Saturday 26 May 2001 01:09, you wrote:
> > Paris (U.E.), le 26/05/2001
> >
> > --- In boost_at_y..., Kevin Lynch <krlynch_at_b...> wrote:
> [...]
> > Square roots do not behave very nicely with quaternions (they give
> > full spheres of answers, and to illustrate, we see immediately that i,
> > j and k are all square roots of -1). There might be some trick with
> Well, even square root for  real/complex numbers don't behave nice.
> Isn't there a 'catastrophe theory' dealing with branching points.
> 
> Best wishes,
> Peter

                Well, "catastrophe theory" is mostly concerned with the 
classification, stability and transformation of some kinds of 
singularites, but that's not very far.

                Indeed, there is some substantial corpus of knowledge in that 
field ("analytic" continuatioon, Riemann surfaces, etc.), even, if I 
recal, some dealing specifically with quaternions. It's just that I 
haven't had the time to correctly explore that aspect. And since I do 
that research in my free time while commuting (my daywork is hardly 
worth mentioning >-< )... and that I have a few other topics of active 
research... it may take some time before I can produce something 
worthwile in that field. But eventually I will tackle that...

        Merci

                        Hubert Holin
                        Hubert.Holin_at_[hidden]