DCRP78/X72R61: Tilt-Pressure Equation and Resonant-Return Infeasibility

Continuing from the two no-X branches left by DCRP77 — the finite/coherent tilt-selection branch T_tilt-sel and the pre-selection branch T_preselect — and drawing on the neutral Floquet threshold from DCRP61–63, the strain-pressure-defect-vorticity bridge from DCRP69, and the 2γ resonant carrier from DCRP76, this round directly confronts the coherent tilt-selection branch. It derives the exact self-similar tilt-pressure equation D_sχ=-(1+2λ)χ-ξ×H_Pξ, and proves that even under the assumption that the X72 response defect vanishes entirely (E_p=0), the resulting moving-frame ODE for the local shape variables (λ,|τ|,a,b) still admits no periodic resonant-return solution — the return equations contradict each other. This establishes that any shape-returning resonant carrier must belong to the X72 state; the only remaining no-X mechanism converges to a noncompact secular material chain (permanent drift or upstream pre-selection), left for DCRP79 to test whether it can remain compact.