This Theorem closes the open assumption θ = π/2 + O(δ_eff) 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 span{I, σ_x, σ_z}, only the R = −σ_y component survives. At leading order (Y = I on the retained sector), the commutator image [M_n, D_n] after diagonal absorption of X carries no symmetric component; the antisymmetric commutator structure suppresses σ_x and σ_z 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(δ_eff) symmetric correction to the transverse projection, giving θ = π/2 + O(δ_eff), where δ_eff parametrizes the off-support leakage of Y on the retained sector. The assumption θ = π/2 + O(δ_eff) 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 δ_eff — 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.
This Theorem closes the open assumption θ = π/2 + O(δ_eff) 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 span{I, σ_x, σ_z}, only the R = −σ_y component survives. At leading order (Y = I on the retained sector), the commutator image [M_n, D_n] after diagonal absorption of X carries no symmetric component; the antisymmetric commutator structure suppresses σ_x and σ_z 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(δ_eff) symmetric correction to the transverse projection, giving θ = π/2 + O(δ_eff), where δ_eff parametrizes the off-support leakage of Y on the retained sector. The assumption θ = π/2 + O(δ_eff) 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 δ_eff — 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.
This Theorem establishes θ = π/2 + O(δ_eff) through a complementary algebraic route to T43: Pauli-basis antisymmetry rather than the null-class pipeline. Two lemmas and two propositions establish the result. The commutator [M,D] = MD − DM is antisymmetric under exchange of operator order by definition, it changes sign under M ↔ D and therefore has no symmetric component. The null-class extraction pipeline suppresses symmetric components: since they do not survive the commutator stage, and Lemma 29.1 eliminates residual symmetric contributions, only antisymmetric components remain on the retained support. Within the Pauli basis {I, σ_x, σ_y, σ_z}, the operators σ_x and σ_z are symmetric under transposition while σ_y is antisymmetric. Therefore, R = −σ_y is the unique antisymmetric generator in the transverse operator space, and at leading order Q⊥ = μR with no σ_x or σ_z content. The Bloch vector is forced to the equatorial plane: θ = π/2. The weighted adjacency operator Y introduces O(δ_eff) off-support leakage, giving h_z = O(δ_eff) and θ = π/2 + O(δ_eff). The two independent derivations of θ = π/2, T43 via null-class pipeline, T45 via Pauli-basis antisymmetry, constitute mutual confirmation of the equatorial forcing. Status: Antisymmetric commutator structure exact, follows from the definition of the commutator alone. Pauli-basis identification of σ_y as a unique antisymmetric generator is exact. Null-class suppression of symmetric components is structurally justified within T26–T29 but not independently derived from explicit kernel generators, same conditionality as T43. The correction term inherits T43 parametric control conditionality. Dependencies: T29, T39, T43, T44.
This collects the T26–T49 arc into a unified structural account of coherence in the reduced phase system. No new operators are introduced. Seven results are established. The observable phase is carried entirely on P⊥ = span{u₂, u₄} with generator A = iσ_y = E_d, A² = −I (T26, T37). Any reduced observable state admits Q⊥ = αI + βσ_z + γσ_x + μA with μ = ½Tr(Q⊥A) (T27); scalar, grading, and off-axis components are annihilated by the extraction functional. Coherence magnitude C := |μ| is nonzero if and only if the transported residue has a nonzero projection onto A. By T29, μ = L̃(Π_sub Π_pair Π_ret([M_n,D_n]Y)), coherence is entirely commutator-driven and transport-weighted. Decoherence occurs precisely when the commutator-driven transverse component fails to survive transport, through four mechanisms: detuning imbalance (T11), transport asymmetry (T31–T33), support leakage outside O_q(s) (T35), or boundary-induced inversion (T47–T49). From T48–T49, each boundary crossing produces a fixed rotational increment (T − I)_rot = (1/160)A plus scalar and symmetric components annihilated by the extraction functional. Three corollaries establish: density matrix correspondence |γ| ∝ |μ|; joint-state coherence condition tied to shared commutator survival; and the equivalence C ≠ 0 ≡ survival of the commutator-driven transverse mode under transport. No Lindblad equation or external decay rate is introduced. The density matrix is a representation of Q⊥, not a physical state postulate. Status: Phase-plane structure, four-parameter Hermitian representation, extraction formula, null-class annihilation, coherence identification, and commutator-driven reduction are all solid within the T26–T38 framework. Failure modes structural, each referenced theorem established the mechanism. (T − I)_rot = (1/160)A conditional on T48 near-identity model and T49 barrier symmetry action. All conditionality entirely inherited from T17, T29, T36, T38, T48, T49: no new assumptions introduced. Dependencies: T11, T26, T27, T29, T31, T32, T33, T35, T37, T38, T47, T48, T49.
This Theorem closes the second open assumption of the T39 bridge lemma by deriving the leg-matching identity a = √2‖v_L‖ + O(δ²_eff) from Q5 carrier structure. Two independent Q5-native mechanisms force the leading-order identity. The complement involution ι: x ↦ 1 − x maps the Hamming-weight-1 subspace isometrically onto the Hamming-weight-2 subspace, intertwines the T24 ambient su(2) action by sign-reversing Ĵ_z and exchanging Ĵ_±, and satisfies ι(v_L) = v_R with ‖v_R‖ = ‖v_L‖. Within the spin-1 module V₁ carried by the Hamming-weight-1 sector, the raising operator Ĵ₊ acts with matrix element √2 between adjacent weight states, a standard spin-1 Clebsch-Gordan coefficient. Combining: at leading order a = √2‖v_L‖, where the √2 is the canonical spin-1 matrix element, not a normalization convention. The Y-transport correction is quadratic not linear: since θ = π/2 + O(δ_eff) from T43, the amplitude scales as sin θ = cos(O(δ_eff)) = 1 − O(δ²_eff), giving a = √2‖v_L‖ + O(δ²_eff). The leading-order result is stable to first order in the off-support leakage. Together with T43, both open assumptions in the T39 bridge lemma are now derived results. Status: Complement isometry solid: direct computation on the residual carrier basis. Spin-1 matrix element solid: standard result. Leading-order leg-matching conditional on identification of transport leg amplitude with Ĵ₊ matrix element on V₁ is structurally natural within the T24–T25 framework but not yet derived from explicit kernel-level transport generators. Quadratic correction inherits T43 parametric control conditionality. All results inherit T22–T25 and T39 conditionality. Dependencies: T22, T24, T25, T39, T43.
T81 establishes the canonical projection of the raw Q5 barrier transport operator onto the reduced phase transport sector. The theorem begins from the first-order raw transport expansionTraw=I+1601A+Snr+O(ϵ2),where\[A=i\sigma_y,\qquadA^2=-I,\]andSnris symmetric/scalar non-rotational dressing arising from the paired transport structure identified in T48. T81 proves that raw purity is false:Snr=0in general. The correct structural statement is instead that the canonical phase-readout projection induced by the T26-T29 extraction pipeline kills the non-rotational dressing:Pphase(Traw)=I+1601A+O(ϵ2)=Tphase. Equivalently,Traw=Nϵ⋅Tphase+O(ϵ2),whereNϵ=I+Snris projection-null symmetric/scalar dressing invisible to the phase-readout sector. The theorem is structurally important because it closes the open gap identified in T80. The continuous phase-flow result\[T_{\mathrm{phase}}^k\toe^{tA}\]no longer depends on manually removing unwanted operator dressing by hand. The T26-T29 extraction architecture canonically projects onto the rotational transport sector from first principles. T81 also marks a conceptual shift in the framework: observable structure is not identified with the full raw operator but with the projection-defined observable sector of a richer transport architecture. The theorem therefore replaces earlier implicit “raw purity” assumptions with observable-sector equivalence under canonical projection. The non-rotational dressing lies in the null-class operator sectorspan{I,σz,σx},while the rotational component1601Asurvives the projection uniquely. Status: solid for the projection-null structure of the non-rotational dressing under the T26-T29 extraction pipeline and for the canonical reductionPphase(Traw)=Tphase;conditional for the near-identity crossing model inherited from T48-T49 and for extension beyond the reduced defect-sector transport plane.
This paper closes the primary open step of the Bear Claws Theorem (T50–T52), the explicit derivation of the coupling parameter β from Q5 kernel geometry, in two parts. Part I derives β = a²/4 and h₁ = √(5/2) directly from matrix computation. The recurrence Y³ = 5Y (T46) pins h₁ = √(5/2) via 2h₁² = 5. Direct multiplication gives [M_n,D_n]·Y = ah₁·[[1,0,1],[0,0,0],[−1,0,−1]], zero middle row and column, consistent with |8⟩ as the defect bond mediation vertex. The visible-hidden coupling is the (1,3) entry ah₁. With Tr(Y^T Y) = 4h₁², β = a²h₁²/(4h₁²) = a²/4. The observable phase coefficient satisfies μ = −8βh₁ = −a²√10. Part II (Theorem 53) establishes that μ, β, and a are not free parameters; they are uniquely determined by compatibility between the kernel-derived phase extraction pipeline (T26–T29) and the transport-level rotational residual (T48–T49). The reduced phase plane is two-dimensional, so its antisymmetric subspace is one-dimensional; any antisymmetric operator surviving the pipeline is a scalar multiple of R = A = E_d = iσ_y. Since both constructions reference the same normalized generator with coefficients μ (extraction pipeline) and 1/160 (transport residual), and the sign is fixed by σ_Γ = −1 from T18: μ = −1/160, β = 1/(1280√(5/2)), a² = 1/(160√10) The value 1/160 is not an imposed normalization; it is the unique coefficient consistent with both the ordered kernel holonomy and the reduced transport evolution. The full chain T17 → T29 → T46 → β = a²/4 → μ = −1/160 → T52 is non-circular. Status: h₁ = √(5/2), product structure of [M_n,D_n]Y, (1,3) coupling entry, Tr(Y^T Y) = 4h₁², and β = a²/4 all solid by direct matrix computation. Generator identification R = A = E_d solid, one-dimensionality of antisymmetric sector is linear algebra. μ = −1/160 solid given generator identification. Sign propagation from T18 through T29, structural, full explicit sign-tracking through the projection pipeline, is the natural supporting calculation. Parametrized form of [M_n,D_n] on {9,8,24} must ultimately be derived from T17 kernel generators to confirm the alternating antisymmetric form is forced rather than assumed. Dependencies: T29, T36, T37, T46, T52.
This Theorem establishes an explicit geometric-phase realization of the Q5 observable coefficient law μ_obs = 4κ_adj + 2κ_non. A closed loop on the Bloch sphere is constructed from six constant-polar-angle azimuthal arcs of equal azimuthal sweep Δφ, four at polar angle θ_adj and two at θ_non. By the standard solid-angle contribution of constant-polar arcs (Ω = Δφ(1 − cosθ)), the total enclosed solid angle is: Ω = 4Δφ(1 − cosθ_adj) + 2Δφ(1 − cosθ_non) The Berry phase of a spin-½ eigenstate adiabatically transported along this loop is γ_Berry = −½Ω. Defining κ_adj := −½Δφ(1 − cosθ_adj) and κ_non := −½Δφ(1 − cosθ_non) gives γ_Berry = 4κ_adj + 2κ_non = μ_obs. The (4,2) multiplicity structure arises geometrically from the decomposition into four adjacent-class and two non-adjacent-class Bloch segments. Status: Solid angle lemma and Berry phase formula are standard results. This is a realization result: it establishes that μ_obs admits a geometric-phase realization. It does not assert that Gray-constrained transport uniquely induces this specific loop, nor that θ_adj and θ_non are fixed by Q5 structure. Uniqueness and intrinsic derivation are addressed in T41. Dependencies: T39.