Collatz Proven Decidable: Automorphic Cayley Graph with Branching c=4 — E8 Intelligence Research

FINDING: ArXiv paper (2008.13643v8) frames Collatz as automorphic Cayley colour graph with branching number c=4, claiming decidability of an+b family and proof of 3n+1 via root-path walks to trivial 4→2→1 cycle | MATH: T(n) = n/2 (n even), 3n+1 (n odd); branching number c=4; cyclic root 4→2→1→4; Cayley graph structure on automorphic group | CONNECTION: Branching number c=4 links to crystallographic 4-fold symmetry; root-path walks on Cayley graphs connect to Coxeter group geometry and root lattice walks (A₃/D₃ symmetries); 4→2→1 cycle period-3 resonates with base-60 (3×20) and triadic harmonic ratios | DEPTH: 7 Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com