It is known that using the Cayley-Dickson construction a quaternion $q$ can be written in a symplectic form as $q=x+\mathbf{i}y$ with $x,y \in \mathbb{C}$.

I read in a couple of references that $x$ is called the *simplex*-part whereas $y$ is called the *perplex*-part of the quaternion. Is this widely accepted and if not what is the proper onomatology?

On the same topic is there a standard name for the two Quaternion parts comprising an Octonion?

pair$(x,y)$ of complex numbers and not in the way that it is written in the question. – José Figueroa-O'Farrill Feb 3 '10 at 18:30