Current Search: Khalil, Saidah Hasan (x)


Title

The CayleyDickson algebras.

Creator

Khalil, Saidah Hasan, Florida Atlantic University, Yiu, Paul Y., Charles E. Schmidt College of Science, Department of Mathematical Sciences

Abstract/Description

This thesis studies the various effects of the nonassociativity of the CayleyDickson algebras At, t>3, especially on the structure of their automorphism groups. Beginning with the problem of composition algebra structures on euclidean spaces, we shall explain the origin of the CayleyDickson algebras, and give a selfcontained exposition on some important results on such algebras. These algebras being nonassociative, we focus on the study of the associators of the form (u,w,v) = (uw)v  u(wv...
Show moreThis thesis studies the various effects of the nonassociativity of the CayleyDickson algebras At, t>3, especially on the structure of their automorphism groups. Beginning with the problem of composition algebra structures on euclidean spaces, we shall explain the origin of the CayleyDickson algebras, and give a selfcontained exposition on some important results on such algebras. These algebras being nonassociative, we focus on the study of the associators of the form (u,w,v) = (uw)v  u(wv). The first main result, that if u and v are elements in a CayleyDickson algebra for which (u, w, v) = 0 for all w, then u and v generate a 2dimensional subalgebra isomorphic to C, was conjectured by P. Yiu, and proved by P. Eakin and A. Sathaye. We shall simplify the proof given by these latter authors. This is then used to give a simple proof of R. D. Schafer's theorem on derivations of CayleyDickson algebras, and following also Eakin and Sathaye, a proof of the conjecture by R. B. Brown on the structure of the automorphism groups of these algebras. Two simple proofs are presented for the beautiful characterization by H. Brandt that in the Cayley algebra A3 = K, conjugation by a unit element a is an automorphism if and only if a is a 6th root of unity. We shall present a geometric proof by M. A. Zorn and a purely algebraic one. The zero divisors of the CayleyDickson algebra A4 are also analyzed in detail.
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Date Issued

1993

PURL

http://purl.flvc.org/fcla/dt/14993

Subject Headings

Cayley algebras

Format

Document (PDF)