Talk:Freudenthal magic square

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Statement disagrees with Hurwitz's Theorem

The article states:

"In addition to the normed division algebras, there are other composition algebras over R, namely the split-complex numbers, the split-quaternions and the split-octonions."

But Hurwitz's theorem (composition algebras) contradicts this, stating that there are no other composition algebras over R besides R itself, the complexes, the quaternions, and the octonions.

Whoever added this statement, please correct it so that it avoids contradicting Hurwitz's theorem.Daqu (talk) 06:49, 8 November 2009 (UTC)[reply]

The article Hurwitz's theorem (composition algebras) has a different definition of composition algebra than the one used in this article, and also a different definition than the article composition algebra itself. I believe one normally talks about "normed division algebras" when talking about Hurwitz's theorem. I'll make some changes. RobHar (talk) 17:17, 22 November 2009 (UTC)[reply]

Quateroctonions

This is not a typo. The 1/4-octonions are a different thing that Rosenfeld also covers. Double sharp (talk) 07:53, 15 April 2016 (UTC)[reply]