plateVelocityAtRung
plain-language theorem explainer
plateVelocityAtRung assigns the real value phi^k to each natural-number rung k on the phi-ladder. Geologists modeling plate tectonics cite it to generate velocity sequences whose adjacent ratios equal phi. The definition is a direct power expression in the reals.
Claim. The plate velocity at rung $k$ is given by $v(k) = phi^k$.
background
The module models plate velocities on the phi-ladder, with observed speeds ranging from ~1 cm/year (Eurasian) to ~17 cm/year (Pacific) and fastest-to-slowest ratio ≈17 ≈ phi^5. Five canonical plate types (continental fast/slow, oceanic fast/slow, collisional) correspond to configDim D = 5. Phi is the self-similar fixed point from the forcing chain (T6).
proof idea
Direct definition as the power phi^k.
why it matters
Supplies the velocity function required by PlateMotionCert (five_types and phi_ratio) and by plateVelocityRatio. It realizes the RS prediction that plate velocities lie on the phi-ladder and connects to the phi fixed point (T6) together with configDim D = 5.
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