# Definition:Cayley-Dickson Construction

Jump to navigation
Jump to search

## Definition

Let $A = \struct {A_F, \oplus}$ be a $*$-algebra.

The **Cayley-Dickson Construction** on $A$ is the procedure which generates a new algebra $A'$ from $A$ as follows.

Let:

- $A' = \struct {A'_F, \oplus'} = \struct {A, \oplus}^2$

where $\struct {A, \oplus}^2$ denotes the Cartesian product of $\struct {A, \oplus}$ with itself.

Then $\oplus'$ and $*'$ are defined on $A'$ as follows:

- $\tuple {a, b} \oplus' \tuple {c, d} = \tuple {a \oplus c - d \oplus b^*, a^* \oplus d + c \oplus b}$
- ${\tuple {a, b}^*}' = \tuple {a^*, -b}$

where:

- $\tuple {a, b}, \tuple {c, d} \in A'$
- $a^*$ is the conjugation of $a \in A$.

This page or section has statements made on it that ought to be extracted and proved in a Theorem page.You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by creating any appropriate Theorem pages that may be needed.To discuss this page in more detail, feel free to use the talk page. |

If $\map \dim {A_F}$ is $d$, then $\map \dim {A'_F}$ is $2 d$.

## Also see

- Cayley-Dickson Construction forms $*$-Algebra
- Results about
**the Cayley-Dickson construction**can be found here.

## Source of Name

This entry was named for Arthur Cayley and Leonard Eugene Dickson.