Jordan 1933: commutative algebra with x²(yx) = (x²y)x. Special: A^+ from associative A. Exceptional Albert algebra h₃(𝕆) over octonions: 27-dim, not special. Foundational in quantum-mechanics observables + projective geometry.
Jordan 1933: commutative algebra with x²(yx) = (x²y)x. Special: A^+ from associative A. Exceptional Albert algebra h₃(𝕆) over octonions: 27-dim, not special. Foundational in quantum-mechanics observables + projective geometry.