We exhibit an algebraic structure underlying color symmetry that arises from mathematical objects already present in Lambda Convergence Universal Field Theory (LUFT). The shape tensors Q^ introduced in the fermion generations analysis ref are real traceless symmetric 3 3 matrices, spanning a 5-dimensional space (3). The -field rotations from the Layer-1 gauge enrichment ref generate the 3-dimensional Lie algebra (3) of antisymmetric matrices. We prove that the direct sum (3) (3) satisfies the three bracket conditions of a Cartan decomposition: (3), (3) (3), (3), (3) (3), and (3), (3) (3). The resulting 8-dimensional Lie algebra is sl (3, ), whose complexification sl (3, C) admits three real forms: sl (3, ) (split), (3) (compact), and (2, 1) (indefinite) ; the Cartan decomposition with k = (3) excludes the third. The associated symmetric space is SL (3, ) /SO (3), whose compact dual is SU (3) /SO (3) (Cartan type AI, rank 2). We argue that the LUFT stability axiom I 0 provides a physical mechanism for selecting the compact form, though this step remains a conjecture. If confirmed, the same M = 3 that produces three fermion generations also produces the sl (3, ) color algebra whose compact dual is (3) ---without postulating non-Abelian gauge groups. Physical implications including color identification, a confinement mechanism, and open problems are discussed with explicit status markers. Version note (v1. 4. 0, July 2026): A/B-sync with the spine v2. 13. 0 retraction: all c2 = A/B statements are replaced — A/B is a quadrature ratio with no kinematic content; the propagation cone is carried by the dispersion route (c2 = alpha*kappa at tree level, conditional on OS reconstruction). The earlier "time emerges from c2 = A/B" phrasing is replaced (time is emergent via the relational Xi-monotone). Terminology: LUFT = Lambda Convergence Universal Field Theory. Algebraic content unchanged.
Ilja Schots (Thu,) studied this question.