Addendum 8: Exponential Backtracking from the Persistent Topological Void

We prove that the persistent 2-dimensional void β2 > 0 in the solution space of random 3-SAT at α = 4.2 (Addendum 7) forces any resolution refutation to have exponential size. This, in turn, implies that any systematic backtracking algorithm (DPLL, CDCL) requires exponential time. Together with the Overlap Gap Property (blocking global algorithms, Addendum 6) and the exponential mixing barrier (blocking local dynamics, Addendum 4), all three obstructions of the Black Hole Trilemma are now established. The final addendum (Addendum 9) will state the theorem P ̸= NP.