This Theorem closes the open assumption θ = π/2 + O (δₑff) from the T39 bridge lemma by deriving it from Q5 transport structure. Two results are established. At leading order, the null-class structure of the T28 extraction functional L forces the Bloch vector to the equatorial plane. The functional L annihilates all operators whose transverse projection lies in spanI, σₓ, σᵦ, only the R = −σᵧ component survives. At leading order (Y = I on the retained sector), the commutator image Mₙ, Dₙ after diagonal absorption of X carries no symmetric component; the antisymmetric commutator structure suppresses σₓ and σᵦ content, leaving the Bloch vector at θ = π/2 exactly. The residual weighted adjacency operator Y is not retained-support invariant (T29, Proposition 29. 4). Its action introduces an O (δₑff) symmetric correction to the transverse projection, giving θ = π/2 + O (δₑff), where δₑff parametrizes the off-support leakage of Y on the retained sector. The assumption θ = π/2 + O (δₑff) in the T39 bridge lemma is therefore not an external imposition but follows from the null-class architecture of the extraction functional and the antisymmetric structure of the transported commutator. This closes the connection between the Berry phase arc (T39–T42) and the commutator-driven extraction pipeline (T26–T29). Status: Part (1) solid within the T29 null-class framework and T17 ordered kernel architecture. Part (2) conditional on the parametric control assumption on δₑff — Y-induced off-support leakage is assumed small and expressible as a controlled perturbation. The antisymmetry argument in Lemma 2 is structurally justified but not independently derived from explicit kernel generators. All results inherit T29 conditionality (remainder null-class decomposability, diagonal absorption) and T17 conditionality. Dependencies: T17, T29, T39, T42.
Craig Edwin Holdway (Sun,) studied this question.