[GiNaC-devel] [offtopic] Quaternions

[Stephen Montgomery-Smith]

Alexei Sheplyakov wrote:
> On Wed, Feb 16, 2011 at 07:34:55AM -0600, Stephen Montgomery-Smith wrote:
>
>>>> Non-commutative complex numbers? What's that?
>>> sorry, I am a mechanical engineer :-)
>>
>> Quaternions.
>
> Also known as (3-dimensional spin 1/2) spinors. I think calling them
> 'complex numbers' is a bit confusing.

Yes - I was giving the poster a lot of the benefit of the doubt.

>
>> Invented by Hamilton
>
> Re-invented by Ehrenfest, Pauli, Dirac, and others. Extensively used in
> quantum mechanics.
>

I didn't know they were reinvented!  They were some very smart people.