Bott-Milnor-Kervaire 1,2,4,8 Theorem

Theorem

Let $A$ be a division algebra with real scalars.


Then the dimension of $A$ is either:

$1$: the real numbers $\R$
$2$: the complex numbers $\C$
$4$: the quaternions $\Bbb H$

or:

$8$: the octonions $\Bbb O$.


Proof


This theorem requires a proof.
You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof.
To discuss this page in more detail, feel free to use the talk page.
When this work has been completed, you may remove this instance of {{ProofWanted}} from the code.
If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page.



Source of Name

This entry was named for Raoul Bott, John Willard Milnor and Michel AndrĂ© Kervaire.


Historical Note

was proved by Raoul Bott, John Willard Milnor and Michel André Kervaire in $1958$.


Sources

  • 1992: George F. Simmons: Calculus Gems ... (previous) ... (next): Chapter $\text {B}.26$: Extensions of the Complex Number System. Algebras, Quaternions, and Lagrange's Four Squares Theorem