Possible Duplicate:
Why is 8 so special?
First of all let me state that I am not a mathematician but I work in computer science and engineering.
I was reading about hypercomplex numbers, and in particular about quaternions and octonions.
My question is is there anything special with the 4 dimensions of the quaternions and with the 8 of the octonions? Why can't we also do hypercomplex numbers with any other arbitrary sum of imaginary parts? For example in 5, 6 or 3 dimensions?