Re: catastrophe

From: Hubert HOLIN (Hubert.Holin_at_[hidden])
Date: 2001-05-28 16:03:39

Paris (U.E.), le 28/05/2001

--- In boost_at_y..., Peter Schmitteckert (boost) <boost_at_s...> wrote:
> Bonjour  Hubert Holin,
> 
> On Saturday 26 May 2001 23:59, you wrote:
> [..]
> 
> > 		Well, "catastrophe theory" is mostly concerned with the
> > classification, stability and transformation of some kinds of
> > singularites, but that's not very far.
> And sqrt(x) is a simple, but important example.
> >
> > 		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...
> 
> You already have this problem with arctan<complex>.
> I would suggest that it's sufficient to document the restirction on the
> import. Once the's branch cut you just can't do it right.
> 
> Best wishes
> Peter

        Hi

                Well, I did document the restrictions (and the reasons for my 
introducing them) just below the "quaternion transcendentals" header. I 
hope to one day re-adress that problem, though...

        A bientot

                        Hubert Holin
                        Hubert.Holin_at_[hidden]