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Moataz
Jan15-09, 06:00 AM
I have recently come across a mathematical reference discussing all
possible generalizations of complex numbers. A particularly
interesting such generalization is known as split-complex numbers.
These are defined:

z = x+jy
z* = x-jy

similarly to ordinary complex numbers except that j^2 = +1 not -1.
This makes:

zz* = x^2 - y^2

Having learned about this for the first time, it immediately brought
memories of a solution in supergravity that I have found but abandoned
on physical grounds some time ago. It seems to me now that the
solution I have found would be well-behaved, at least mathematically,
if I had assumed it to be split-complex! But this begs the question:
What does that mean physically? Do any of you know of any precedent in
the literature.
I am just curious, but perhaps I will take a second look at that
solution ...

Igor
Jan15-09, 06:00 AM
On Jan 14, 6:00*pm, Moataz <Moataz.E...@gmail.com> wrote:
> I have recently come across a mathematical reference discussing all
> possible generalizations of complex numbers. A particularly
> interesting such generalization is known as split-complex numbers.
> These are defined:
>
> z = x+jy
> z* = x-jy
>
> similarly to ordinary complex numbers except that j^2 = +1 not -1.
> This makes:
>
> zz* = x^2 - y^2
>
> Having learned about this for the first time, it immediately brought
> memories of a solution in supergravity that I have found but abandoned
> on physical grounds some time ago. It seems to me now that the
> solution I have found would be well-behaved, at least mathematically,
> if I had assumed it to be split-complex! But this begs the question:
> What does that mean physically? Do any of you know of any precedent in
> the literature.
> I am just curious, but perhaps I will take a second look at that
> solution ...


These are sometimes referred to as hyperbolic complex numbers. The
factor j can be identified with a real unitary matrix. More can be
found here:

http://en.wikipedia.org/wiki/Split-complex_number