Arnold map: φ_{n+1}=φ_n+Ω−K·sin(2πφ)/(2π); d_map=1−K·cos(2πφ); λ(K=0)=0

Sympy-exact symbolic witness of the Arnold circle-map canonical iterative form, derivative, and K=0 rigid-rotation anchor. Setup: phi_n, Omega_cm, K_cm — all positive symbols. Circle-map iteration: T(φ_n) = φ_n + Ω − K·sin(2π·φ_n)/(2π)…