Cherenkov anchor: cos(θ_C)(β·n=2) = 1/2; θ_C = π/3

Sympy-exact witness of the Cherenkov cone-angle canonical anchor. Setup: cos(θ_C) = 1/(β·n) — a two-symbol rational function. Identity: at the superluminal-factor-2 anchor β=1, n=2 (product β·n = 2), cos(θ_C) = 1/2, so θ_C = arccos(1/2)…