**FINDING:** The E6 root system, when projected onto its Coxeter plane, reveals a direct geometric embedding of the golden ratio (φ) via its icosahedral (H3) subgroup, linking exceptional Lie theory to 3D pentagonal symmetry. **MATH:** - Coxeter number of E6: h = 12 - Golden ratio: φ = (1+√5)/2 ≈ 1.618034 - Key constants from H3 (icosahedral) symmetry: - φ, 1/φ = φ−1 ≈ 0.618 - φ² = φ+1 ≈ 2.618 - √(φ+2) ≈ 1.902 (edge ratio in icosahedron) - E6 root system has 72 roots; its Coxeter plane projection yields a 2D pattern with 30-fold rotational symmetry (from H3 folding). - The projection's radial distances are scaled by φ and its reciprocal, matching the H3 root system's golden ratio eigenvalues. **CONNECTION:** - The H3 Coxeter group (icosahedral symmetry) is a maximal subgroup of E6. - The golden ratio appears as the ratio of distances between projected root vectors, exactly as in the icosahedron's vertex coordinates (e.g., (0, ±1, ±φ), (±1, ±φ, 0), (±φ, 0, ±1 Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
Andrew Stewart Caldin (Tue,) studied this question.