Questions tagged [octonions]

For questions on the octonions, a normed division algebra over the real numbers. It is a non-associative higher-dimensional analogue in the hierarchy of real, complex, and quaternionic numbers.

In mathematics, the octonions are a normed division algebra over the real numbers, usually represented by the capital letter ${\mathbb O}$. There are only four such algebras, the other three being the real numbers $\Bbb R$, the complex numbers $\Bbb C$, and the quaternions $\Bbb H$. The octonions are the largest such algebra, with eight dimensions, double the number of the quaternions from which they are an extension. They are noncommutative and nonassociative, but satisfy a weaker form of associativity, power associativity.

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A real example of an Octonion product

Goal: find the general Octonion multiplication product like the Quaternion formula given here: https://en.wikipedia.org/wiki/Quaternion#Multiplication_of_basis_elements * question modified for clarity I am having trouble with Octonion…
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Using the Fano plane for octonion multiplication

The Fano plane is the projective plane over the field $\mathbf Z/2$. It can be used to remember octonion multiplication, as nicely explianed in John Baez's article on octonions (see http://math.ucr.edu/home/baez/octonions/). The picture (taken from…
Oblomov
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Are H$_n$(O) (n>3) Jordan algebras?

As we know, H$_3$(O) is a 27-dimensional exceptional Jordan algebra, here O is Cayley octonion algebra.But how about n>3? I guess that when n>3, H$_n$(O) are not Jordan algebras. But I only have a virtual reason: if they are also Jordan algebras,…
Strongart
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Is octonion structure related to the fact that an 8-cube has an equal number of 2-faces and 3-cells?

Background: We know that octonions exist in 8-space, and we know that in 8-space, the 8-dimensional "measure polytope" ("hypercube") just so happens to have the SAME number of 2-dimensional faces (squares) and 3-dimensional cells (cubes). (This…
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Construction of the Octonions

I get how to construct number systems: $\Bbb{N,~Z,~Q,~R,~C}$. But what about the hypercomplex? How do we go from $\Bbb C$ to $\Bbb H$ and $\Bbb O$? I've also heard it stated that the octonions are the "center" of mathematics. If that's true, then…
QWERTY_dw
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Why this is the octonions?

The multiplication table is different from that of the octonions what I know. I tried to find suitable basis change for which the multiplication table coincide with wikipedia, but no success.
LHS
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