Variational Backbone and Regime Closures III: R3 Retained Laws from the Core Density R3 Time Completion, Summary Footprints, and Gate-Restricted Standard-Like Branches

VBRC treats conservative time-completed dynamics as a retained-law interface ratherthan as a primitive textbook equation. Under the Internal Invisibility Principle, the unreadsector cannot be assigned direct retained status; in this Part it contributes to R3 only throughthe licensed summary footprint F = ΣH,P (II ) (represented in the Part III first-order branchby F = DI II ), producing a standard-like retained law with a licensed unread-summary entry.This paper computes the R3 retained law generated directly by the Part I core densityecore =β2|DRIR|2 +α2|F|2 + η ⟨IR, F⟩, F = ΣH,P (II ).In the Part III first-order representative, F = DI II . R3 time-completion is imposed only onthe retained variable IR; the unread variable II is not assigned an independent kinetic term.The retained first variation isδEcoreδIR= βD∗RDRIR + ηF,and the resulting R3 Euler–Lagrange law isa ∂2tIR + βD∗RDRIR + ηF = 0.Thus the unread sector affects the retained R3 law only through the licensed summary F;conservation is a further regime statement depending on the chosen F-gate. The genericVBRC retained law is therefore not a textbook equation: it is a standard-like retainedbackbone together with a licensed unread-summary footprint. This footprint is the structuralsignature of the Internal Invisibility Principle (IIP) inside the retained law, not an error termadded after the fact.The summary channel is then treated by explicit F-gates. Two core-admissible summarychannel treatments are used in Part III. Under (GF 1), F = FP (t, x) is a protocol-given load.Under (GF 2), instantaneous summary-stationarity givesF = −ηαPF IR, PF = PRan(DI ),so that the retained law becomesa ∂2tIR + βD∗RDRIR −η2αPF IR = 0.Unread-side time-completion with an independent term ν2∥∂tII ∥2is recorded only as thenon-core extension gate (GF 3).The Klein–Gordon, Schrödinger, and Hamilton–Jacobi equations are not starting points ofthis Part and are not the generic output of the retained R3 calculation. They are downstream,gate-restricted readouts obtained only after the licensed summary footprint is represented,localized, stabilized, or re-expressed as effective lower-order data; only in special degeneratebranches does the footprint vanish. Thus the footprint remains part of the R3-generatedlaw-space rather than being erased to recover a textbook equation. The R2/R3 hierarchyis fixed: R2 selects or stabilizes the background representative, while Part III studies R3retained oscillations on that selected M0/R2-frozen branch.