subduction_speed
plain-language theorem explainer
Subduction velocity is defined as the reference seismic scale divided by phi to the seventh power. Plate boundary modelers cite this for placing subduction rates on the Recognition Science phi-ladder of geological timescales. The declaration is a direct definition that supplies the value for downstream ratio and inequality theorems.
Claim. The subduction speed is given by $v_ {sub} = c_{seismic} / phi^7$, where $c_{seismic}$ is the dimensionless reference seismic velocity scale.
background
The module places plate boundary velocities on the phi-ladder of geological timescales, with mantle convection supplying the seismic velocity scale. Subduction speed occupies rung 7 while ridge spreading occupies rung 9, yielding the ratio phi squared. The upstream definition c_seismic fixes the reference scale at unity in RS-native units.
proof idea
The declaration is a direct definition that assigns the expression c_seismic / phi ^ 7. No lemmas are applied beyond the definition of c_seismic and the power operation.
why it matters
This definition supplies the subduction speed field to the master certificate PlateBoundaryDynamicsCert, which asserts the ratio equals phi squared and subduction exceeds ridge spreading. It fills the subduction velocity slot in the module's §XXIII.C geology row, using the phi-ladder scaling from the self-similar fixed point. The value enables the proved interval for Wilson cycle lower bounds.
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