Nonassociative Algebras
Published in Leslie Hogben, Richard Brualdi, Anne Greenbaum, Roy Mathias, Handbook of Linear Algebra, 2006
Murray R. Bremner, Lucia I. Murakami, Ivan P. Shestakov
Real division algebras [EHH91, Part B]. In the previous example, taking F to be the field ℝ of real numbers and a = b = c = −1, we obtain the field ℂ of complex numbers, the associative division algebra ℍ of quaternions, and the alternative division algebra 𝕆 of octonions (also known as the Cayley numbers). Real division algebras exist only in dimensions 1, 2, 4, and 8, but there are many other examples: The algebras ℂ, ℍ, and 𝕆 with the multiplication x⋅y=x¯y¯ are still division algebras, but they are not alternative and they are not unital.