Bioctonion
In mathematics, the algebra of bioctonions, or complex octonions, is the tensor product of the algebra of octonions and the algebra of complex numbers. It is often denoted or.
Thus, every bioctonion can be written as a + bi where a and b are octonions. Addition of bioctonions is defined by
and multiplication of bioctonions is defined by
We can define the conjugate of a bioctonion by
There is another equivalent scheme which obtains the bioctonions by repeated application of the Cayley–Dickson construction starting from the field of complex numbers, the trivial involution, and quadratic form z2.
Applying this construction once we obtain the biquaternions, and applying it again we obtain the bioctonions. This approach exhibits the bioctonions as an octonion algebra over the complex numbers.
Concretely, in this approach a bioctonion is written as a pair where p and q are biquaternions. Addition of bioctonions is then defined by
while multiplication of bioctonions is defined using biquaternion multiplication and the biconjugate of a biquaternion p, as follows:
In this approach the bioctonion z = has conjugate z* =, and the norm N of bioctonion z is z z* = p p* + q q*, which is a complex quadratic form with eight terms. For any pair of bioctonions y and z,
showing that N is a quadratic form admitting composition. Thus, the bioctonions form a composition algebra over the complex numbers.
Guy Roos explained how bioctonions are used to present the exceptional symmetric domains:
Complex octonions have been used to describe the generations of quarks and leptons.