Newton's Third Law states: for every action, there is an equal and opposite reaction. In the Koku Universe framework (U = T x G), action and reaction are not two forces — they are one phenomenon viewed from two directions simultaneously. When two bodies contact, their Koku-plane layer densities form an interface. The gradient ∇ (1/N) at that interface manifests as equal and opposite vectors on each side. Action-reaction is the topological necessity of a symmetric interface in a layered universe. One gradient. Two faces. One truth. Third paper in the classical mechanics unification chain: Paper 1 (vₜ ∝ 1/N), Paper 2 (F = ∇ (1/N) ), Paper 3 (this paper). Part of TheYKHC Koku Universe Research Series.
Yoshimitsu Katayama (Thu,) studied this question.