FINDING: E8 lattice projection to 3D icosahedral quasicrystal via cut-and-project method yields golden ratio in all inter-vertex distances. | MATH: E8 root system has 240 vertices in 8D; projection to 3D uses a 3D subspace (physical space) and a 5D orthogonal subspace (phason space). The cut-and-project method selects points from the E8 lattice whose projection onto phason space falls within a defined window (typically a 3D icosahedral acceptance domain). The resulting 3D quasicrystal has vertices with distances scaled by powers of φ = (1+√5)/2 ≈ 1.618034, and the ratio of long to short edges in the icosahedral tiling is φ. The quaternion orientational order parameter Q = q₀ + q₁i + q₂j + q₃k with |Q| = 1 describes icosahedral symmetry via the binary icosahedral group (order 120). | CONNECTION: Direct: φ appears as the fundamental scaling factor in the 3D quasicrystal tiling (e.g., Ammann–Mackay icosahedral tiling). The E8 lattice itself has Coxeter number 30, and its Cartan matrix eig Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
Andrew Stewart Caldin (Mon,) studied this question.