lattice-system

Legacy long-form records: Spin models, Chapters 3–7, and spectral tools, part 2

Interim authority. These records contain long statement and implementation-history cells moved from the legacy catalogue tables for readability. Each record is linked exactly once from its original table position.

Interim catalogue

Record from former line 621

Lean name: ringBondSquareConst_reindexCyclic / ringBondSquareLinField_reindexCyclic / ringBondSquareFieldPartitionRe_pos / ringBondSquareFieldPartitionRe_reindexCyclic / ringBondSquareFieldPartition_gaussianDomination

File: Quantum/SpinS/RingReflectionBondSquareGaussianDomination.lean

Statement and implementation chronicle:

Bond-square chessboard Gaussian-domination capstone (RingReflectionBondSquareGaussianDomination.lean, Tasaki §4.1 Lemma 4.5 + Theorem 4.2 (4.1.55)–(4.1.57) + (4.1.51), book pp. 87–90, bond-square chessboard Gaussian-domination / PR #4998): the finite-β chessboard Gaussian-domination bound Z^{BS}_β(h)^{2n} ≤ ∏_j Z^{BS}_β(fun _ => h j) (Tasaki §4.1 Theorem 4.2, pp. 85–90;

chessboard estimate Lemma 4.5, (4.1.55)–(4.1.57), pp. 87–88), obtained by applying the classical cyclic averaging inequality (reflectionPositivity_averaging, Tasaki Lemma 4.5, (4.1.55)–(4.1.57), pp. 87–88) directly to the plain functional F g = −log Z^{BS}_β(g) — no staggered-relabel bridge needed, since PR-BS8b already delivers the reflection step on the sign-free classical mirrors. Cyclicity hypothesis (★★ hcyc) (4.1.55) ringBondSquareFieldPartitionRe_reindexCyclic (PR-BS9, RingReflectionBondSquareFieldPartition.lean): Z^{BS}_β(reindexCyclic n g) = Z^{BS}_β(g), proved from the scalar-shift reduction (★★) (ringBondSquareFieldPartitionRe_eq_scaled). The scalar constant C(h) is translation-invariant (A) ringBondSquareConst_reindexCyclic (PR-BS9, RingReflectionBondSquareField.lean);

the linear field covariance kOf(reindexCyclic h) = −kOf(h) (B) ringBondSquareLinField_reindexCyclic (PR-BS9, RingReflectionBondSquareField.lean), a sign flip absorbed by spin-flip invariance ringFieldPartitionRe_neg and translation symmetry ringFieldPartitionRe_translate of the linear-core partition. Positivity domain (4.1.56) ringBondSquareFieldPartitionRe_pos (PR-BS9, RingReflectionBondSquareFieldPartition.lean, strict positivity 0 < Z^{BS}_β(h)) is required for the −log functional;

follows from the scalar-shift reduction and positivity of both factors. Reflection bound (4.1.56): the one reflection step (PR-BS8b) Z^{BS}_β(g)² ≤ Z^{BS}_β(reflectLeft n g)·Z^{BS}_β(reflectRight n g) on classical mirrors, combined with positivity. Averaging computation: applying reflectionPositivity_averaging yields (1/2n) Σ_j (−log Z^{BS}_β(fun _ => h j)) ≤ −log Z^{BS}_β(h). Exponentiating and rearranging gives the product bound. Forward to PR-BS10: PR-BS10 collapses each constant-field factor to Z^{BS}_β(0), yielding the uniform-field bound Z^{BS}_β(h) ≤ Z^{BS}_β(0) (Tasaki (4.1.49)/(4.1.52), pp. 85–86). This is PR-BS9 of the bond-square route toward the reflection-positivity infrastructure for Theorem 4.2.

Record from former line 653

Lean name: staggeredCasimirOpS / shenQiuTian_ferrimagnetic_lro

File: Quantum/SpinS/FerrimagneticLROUniversalFinal.lean + …UniversalFinalCore.lean + FerrimagneticLRO.lean + …ComponentAlgebra.lean + …CrossTerm.lean + …TotalSpin.lean + …TotalSpinCore.lean + …Capstone.lean + …Universal.lean

Statement and implementation chronicle:

Theorem 4.4 (§4.1, Shen–Qiu–Tian, PROVED axiom-free;

eqs. (4.1.12)–(4.1.13)): ferrimagnetic LRO on an asymmetric bipartite lattice. The SU(2)-invariant squared staggered operator (Ô_Λ)² = Σ_{x,y} ε_x ε_y Ŝ_x·Ŝ_y, and the bound S²(\|A\|−\|B\|)² ≤ ⟨Φ_GS\|(Ô_Λ)²\|Φ_GS⟩ for any normalized ground state of the connected bipartite AFM model (same hypotheses as Thm 2.3). PROVED axiom-free (Issues #4604/#4617 CLOSED;

book proof = chain (4.1.16): (4.1.15) cross-term + Lieb–Mattis Thm 2.3 total spin + Casimir). PR1 (#4605) formalizes the operator-algebra core in Quantum/SpinS/FerrimagneticLROComponentAlgebra.lean: staggeredTransverseCasimirOpS (transverse part of (Ô_Λ)²), (Ô_Λ)² = transverse + (Ô_Λ^(3))², the PSD drop ⟨transverse⟩ ≤ ⟨(Ô_Λ)²⟩, (Ŝ_tot^(α))² = Σ_{x,y} Ŝ_x^(α)Ŝ_y^(α), the Casimir identity Σ_{x,y}(Ŝ_x^(1)Ŝ_y^(1)+Ŝ_x^(2)Ŝ_y^(2)) = (Ŝ_tot)² − (Ŝ_tot^(3))², and the M=0 reduction ⟨(Ŝ_tot)²⟩ = ⟨transverse⟩. PR2 (#4606) adds the cross-term inequality (4.1.15) in Quantum/SpinS/FerrimagneticLROCrossTermCore.lean (transverse correlation + ladder positivity + per-pair sign) + Quantum/SpinS/FerrimagneticLROCrossTerm.lean (the summed cross-term inequality, split for build speed): the transverse correlation ⟨Φ,T_xy Φ⟩ (T_xy = ½(Ŝ_x^+Ŝ_y^- + Ŝ_x^-Ŝ_y^+)), its non-positivity for cross-sublattice pairs on a Marshall-positive sector ground state (marshallSignS·c, c>0), and the summed dominance ⟨Φ,(Σ_{x,y}T_xy)Φ⟩.re ≤ ⟨Φ,staggeredTransverseCasimirOpS Φ⟩.re. PR3 (#4607) adds the total-spin value in Quantum/SpinS/FerrimagneticLROTotalSpin.lean (coupling-agnostic via a tasaki_2_5_theorem_2_3 hypothesis): exists_centered_groundState_predictedCasimir_of_tasaki23 produces a centered (Ŝ³_tot Φ⁰=0) Marshall ground state with (Ŝ_tot)² Φ⁰ = S_tot(S_tot+1)·Φ⁰ (S_tot=(\|A\|−\|B\|)N/2), reusing tasaki23_pf_groundState_casimir_eq_predicted_sector + the extremal-Casimir machinery. PR4 (#4608) proves the capstone ferrimagnetic_lro_completeBipartite_centered in Quantum/SpinS/FerrimagneticLROCapstone.lean: assembling chain (4.1.16) on the centered ground state, (N/2)²(\|A\|−\|B\|)²·⟨Φ⁰,Φ⁰⟩.re ≤ ⟨Φ⁰,(Ô_Λ)²Φ⁰⟩.re (existence form, coupling-agnostic via tasaki_2_5_theorem_2_3;

sorry-free, axiom-clean, independent of the shenQiuTian_ferrimagnetic_lro axiom;

that axiom is now itself proved in UniversalFinal). For build speed the proof’s private Rayleigh-ratio helpers and the per-sector oriented bound staggeredCasimir_weightComponent_bound_oriented (now module-public: S_tot²·‖Φ_M‖² ≤ ⟨Φ_M,(Ô_Λ)²Φ_M⟩.re for each magnetization weight component Φ_M of a ground state) live in the companion …UniversalFinalCore.lean, with the sum assembly + the public shenQiuTian_ferrimagnetic_lro kept in …UniversalFinal.lean.

Record from former line 654

Lean name: raiseLowerReachableS_of_connected

File: Quantum/SpinS/ConnectedRaiseLower.lean + …ConnectedDressedPF.lean + …ConnectedSectorIrreducible.lean + …ConnectedTheorem23Core.lean + …ConnectedTheorem23.lean + …ConnectedFerrimagneticLRO.lean + …StaggeredCasimirSU2Invariance.lean + …SU2ExpectationLadderInvariant.lean + …SU2ExpectationLadderIterated.lean + …ConnectedSectorFinrankLeOne.lean + …WeightPreservingExpectationSum.lean + …StrictHOutsideFerrimagnetic.lean + …StrictHOutsideFerrimagneticCore.lean + …FerrimagneticLROUniversal.lean

Statement and implementation chronicle:

Connected-graph spin-config reachability (§2.5, PROVED; Issue #4609, prereq for the connected Marshall–Lieb–Mattis extension / Thm 4.4 axiom): on a connected graph G, any two equal-magnetization configs are raise/lower reachable — G.Connected → magSumS σ = magSumS σ' → RaiseLowerReachableS G σ σ'. Discharged axiom-free by strong induction on the configDistS mismatch (surplus/deficit sites + connected-graph walk) with overflow-safe single-quantum path transport (transportOne; at each edge push the quantum forward when the next vertex has room, else recurse first to make room). Generalizes the complete-bipartite raiseLowerReachableS_bipartiteCompleteGraph to arbitrary connected graphs — the combinatorial core of extending Theorem 2.3 to connected couplings (PR #4610). PR2 (#4611) lifts this to the dressed-matrix per-sector Perron–Frobenius positivity for a general connected bipartite G in Quantum/SpinS/ConnectedDressedPF.lean: exists_matrixPow_pos_of_magConfigS_connected (∃ k, 0 < (shiftedDressedSReMatrixOnMagSector A J N c M)^k σ' σ) from G.Connected + hGbip + edge-positivity hJ_pos_G : G.Adj x y → 0 < (J x y).re (not complete-bipartite positivity), via the graph-agnostic edge-local witness neg_dressedHeisenbergSReMatrix_apply_pos_of_raiseLowerStepS_witness + the connected reachability — generalizing exists_matrixPow_pos_of_magConfigS_bipartite. PR3 (#4612) assembles Theorem 2.3 itself for connected couplings: isIrreducible_shiftedDressedSReMatrixOnMagSector_connected (ConnectedSectorIrreducible.lean) + 20 _of_irreducible chain variants parameterizing the PF-consuming Marshall–Lieb–Mattis chain by the irreducibility result (graph-agnostic) + the capstone tasaki_2_5_theorem_2_3_data_of_connected (ConnectedTheorem23Core.lean, ConnectedTheorem23.lean): the per-magnetization-sector Marshall-positive ground states + global minimality of Theorem 2.3 hold for ANY connected bipartite J (G.Connected + hGbip + edge-positivity hJ_pos_G), not just complete-bipartite — the hOutside/lower-bound side reuses tasaki23_general_hOutside/tasaki23_eigenvalue_ge_common (which need only hJ_nn). This is the connected-coupling extension of Marshall–Lieb–Mattis (Lieb–Mattis 1962). PR4 (#4613) assembles the connected-coupling ferrimagnetic LRO bound (existence form) ferrimagnetic_lro_connected_centered (ConnectedFerrimagneticLRO.lean): for any connected bipartite AFM coupling (G.Connected + hGbip + hJ_pos_G), there is a centered ground state Φ⁰ with (N/2)²(\|A\|−\|B\|)²·⟨Φ⁰,Φ⁰⟩.re ≤ ⟨Φ⁰,(Ô_Λ)²Φ⁰⟩.re — Tasaki’s chain (4.1.16) for the genuine connected (non-complete) coupling, built from the connected Theorem 2.3 data + connected irreducibility Casimir value + the PR1/PR2 operator-algebra (all graph-agnostic). PR5 (#4614) proves the SU(2) invariance of (Ô_Λ)² in Quantum/SpinS/StaggeredCasimirSU2Invariance.lean: staggeredCasimirOpS_commute_totalSpinSOp{1,2,3} + …OpPlus/…OpMinus (the squared staggered order operator commutes with every total-spin operator), immediate from the per-pair spinSDot_commutator_totalSpinSOp* vanishing — ingredient (a) of the universal-form transfer. PR6 (#4615) proves the core of ingredient (b) in Quantum/SpinS/SU2ExpectationLadderInvariant.lean: su2_expectationRatioRe_ladder_invariant — for an SU(2)-invariant operator O (commuting with Ŝ^±_tot) and a joint Ŝ³_tot/Casimir eigenvector v, the real expectation ratio ⟨w,Ow⟩.re/⟨w,w⟩.re is unchanged under lowering w ↦ Ŝ⁻_tot v (both numerator and denominator scale by the same Ŝ⁺Ŝ⁻ = Casimir − (Ŝ³)² + Ŝ³ eigenvalue). This is the ladder step that makes (Ô_Λ)²’s expectation constant across the spin-S_tot multiplet;

PR7 (#4616) iterates it to (Ŝ⁻_tot)^k (su2_expectationRatioRe_ladder_iterate_invariant, Quantum/SpinS/SU2ExpectationLadderIterated.lean), so every member of the lowering tower shares the centered ratio. The stated shenQiuTian_ferrimagnetic_lro axiom (universal over all ground states) now remains pending only the final assembly of ingredient (b): the ground-state weight decomposition + the ground-eigenspace classification (any global-min eigenvector’s nonzero Ŝ³-weight components lie in the admissible sectors — needs strict energy separation, the hard remaining gate) (#4604). PR8 (#4618) adds step 1 of that dimension bound: heisenbergHamiltonianSMatrixOnMagSector_finrank_le_one_of_marshall_positive_connected (Quantum/SpinS/ConnectedSectorFinrankLeOne.lean) — connected-coupling per-sector ground-state uniqueness (finrank ≤ 1), the connected-irreducibility mirror of the complete-graph lemma (Issue #4617). PR9 (#4619) adds step 3: weightPreserving_expectation_eq_sum_sector (Quantum/SpinS/WeightPreservingExpectationSum.lean) — for any operator commuting with Ŝ³_tot, ⟨Φ,OΦ⟩ = Σ_M ⟨Φ_M,OΦ_M⟩ over the Ŝ³-weight sector components (cross terms vanish by Ŝ³_tot-eigenvalue orthogonality; no Hermiticity of O needed), the block-diagonal decomposition for (Ô_Λ)²’s expectation. PR10 (#4620) clears the hard gate (step 2): tasaki23_strict_hOutside_of_connected (Quantum/SpinS/StrictHOutsideFerrimagnetic.lean; for build speed the per-sector ferrimagnetic foundation tasaki23_strict_hOutside_ferrimagnetic and its Casimir-obstruction helpers live in the companion …StrictHOutsideFerrimagneticCore.lean) — strict energy separation, μ < μM for any non-admissible sector M ∉ [min·N, max·N] (the connected ferrimagnetic generalization of the balanced tasaki23_strict_hOutside_of_card_eq_zero_casimir_ladder_obstruction, via the Casimir equality-obstruction: ladder a hypothetical non-admissible μ-eigenvector to the admissible band edge, pull back the predicted Casimir S_tot(S_tot+1) through the ladder, contradict the abs Casimir lower bound |center−M|(|center−M|+1) > S_tot(S_tot+1)). This is the strict Lieb–Mattis level ordering for the connected AFM Heisenberg — the last gate; only the final weight-decomposition assembly remains to discharge shenQiuTian_ferrimagnetic_lro (#4617). PR11 (#4621) adds the universal-form assembly infra in Quantum/SpinS/FerrimagneticLROUniversal.lean: chain_bound_marshall_sector (Tasaki’s chain (4.1.16) at an arbitrary-weight Marshall sector vector: (γ − m²)‖w‖² ≤ ⟨w,(Ô_Λ)²w⟩.re), star_dotProduct_self_eq_sum_sector (‖Φ‖² = Σ_M ‖Φ_M‖²), heisenbergHamiltonianS_magSectorProjection_eigen (a weight component of an H-eigenvector is an H-eigenvector), the diagonal-shift c existence, and the global-flip / weight-commute helpers. The remaining step to remove the axiom is the SU(2) Rayleigh-ratio constancy across the spin-S_tot multiplet (transfer the per-sector bound from a near-central admissible sector to all sectors via the merged iterated ladder-invariance) (#4617)

Record from former line 664

Lean name: orderSum_pow_two_denom_close / staggeredPhatS_manyBodyOperatorNormS_le / phatMoment_succ_le_normSq / orderSum_pow_phat_insert_close / tanakaOrderSecond2_eq_half_sum / tanaka_delta_eq / tanaka_delta_le / tanakaOrderSecond2_le

File: Quantum/SpinS/AndersonTowerEnergyBound.lean, Quantum/SpinS/AndersonTowerTanakaFluctuation.lean

Statement and implementation chronicle:

Theorem 4.9 axis-2 transverse fluctuation decay (§4.2.2, Tasaki Theorem 4.9 discharge PR4, #4971;

eqs. (4.2.15)/(4.2.33)/(4.2.34)/(4.2.49)–(4.2.55)): the Tanaka state vanishes in the axis-2 direction (transverse to axis-1 SSB). The mechanism (the tower u_k is built from the axis-1 operator Ô_L^{(1)} = (V/2) Ã, Ã = ô⁺ + ô⁻, while the measured transverse observable is (ô^{(2)})² with ô^{(2)} = (2i)⁻¹(ô⁺ − ô⁻)): per-site transverse fluctuation δ_k := ⟨u_k| (ô^{(2)})² |u_k⟩ = Q_k − R_k with Q_k = E_k/D_k (single p̂-insertion, numerator E_k = ⟨Φ, Ã^k p̂ Ã^k Φ⟩), R_k = D_{k+1}/(4D_k) (ratio of denominators), D_k = ⟨Φ, Ã^{2k} Φ⟩. (F1) Two-sided denominator closeness (orderSum_pow_two_denom_close, eq. 4.2.42): |D_{m+1} − C(2(m+1),m+1) P_{m+1}| ≤ C(2(m+1),m+1) · (m+1)² (N/V) (3/2 P_m) via balanced-word expansion + fine bound orderWord_balanced_re_close_fine (eq. 4.2.34). (F2) Numerator closeness with p̂ insertion (orderSum_pow_phat_insert_close, eq. 4.2.50): |E_k − C(2k,k) P_{k+1}| ≤ ... via length-2(k+1) balanced-word expansion with central p̂ + Vandermonde counting. (Gap2) Rayleigh power ratio (staggeredPhatS_manyBodyOperatorNormS_le, phatMoment_succ_le_normSq): P_{k+1} ≤ N² P_k and ‖p̂ u_k‖² ≤ P_{k+1}. (F3) Per-site fluctuation decomposition (tanakaOrderSecond2_eq_half_sum): second2 = ½(δ_M + δ_{M+1}) (tower-term average). (F4) δ_k bound and capstone (tanaka_delta_eq, tanaka_delta_le, capstone tanakaOrderSecond2_le): δ_k ≤ P_{k+1}/(D_k·2k+2) ≤ N²/(2k+2) + O(1/V) from Pascal ratio (k+1) C(2k+2,k+1) = 2(2k+1) C(2k,k) ⟹ second2 ≤ ε as L→∞. Lemmas: staggeredPhatS_manyBodyOperatorNormS_le (p̂ norm), phatMoment_succ_le_normSq (ratio). Status: the section tip tanakaOrderSecond2_le is a proved theorem (all of F1–Gap2–F3–F4 discharged axiom-free);

the overall Theorem 4.9 (tanakaSSB_full_symmetry_breaking) is now itself a proved theorem, discharged in PR5 (#4972) by assembling this finite-L bound with the explicit tower sequence M(L) = ⌊L^{d/4}⌋ (see the Theorem 4.9 capstone row)

Record from former line 687

Lean name: stagOpVec_commutator_eq / totalSpinSOpVec_mul_cartWord_eq / totalSpinSOpVec_mulVec_cartWord_singlet / orderComm_mulVec_cartWord_singlet / cartWord_swap_dotProduct_eq

File: Quantum/SpinS/AndersonTowerTelescoping.lean

Statement and implementation chronicle:

Cartesian order-word swap-band telescoping (Tasaki §4.2.2, Prop 4.10;

PROVED axiom-free, Issue #4974, PR #5018): the three-part telescoping crux (push-through + singlet boundary erasure + single-swap expectation identity) that resolves Cartesian order-word contraction in Proposition 4.10’s sphere-average argument. Uniform order×order commutator (stagOpVec_commutator_eq): merges six off-diagonal and three diagonal commutators into [ô^{(α)}, ô^{(β)}] = i Σ_γ ε_{αβγ} Ŝ^{(γ)}_tot, feeding the swap-diff factorization cartWord_swap_diff_eq. Operator telescoping identity (totalSpinSOpVec_mul_cartWord_eq): pushing total-spin generator Ŝ^{(γ)}_tot through Cartesian order word ô^{w} via the uniform commutator yields the length-preserving identity Ŝ^{(γ)}_tot · ô^{w} = ô^{w} · Ŝ^{(γ)}_tot + i Σ_k Σ_δ ε_{γ w_k δ} ô^{w[k ↦ δ]}, where w[k ↦ δ] is the word with its k-th letter rotated. Singlet corollary (totalSpinSOpVec_mulVec_cartWord_singlet): on a total-spin singlet Φ (annihilated by Ŝ³_tot and Ŝ¹_tot, hence by Ŝ²_tot via totalSpinSOp2_mulVec_eq_zero_of_singlet), the leading term vanishes, leaving the pure rotation sum Ŝ^{(γ)}_tot (ô^{w} Φ) = i Σ_k Σ_δ ε_{γ w_k δ} (ô^{w[k ↦ δ]} Φ) — the boundary erasure that allows Prop 4.10 to survive. Intermediate helper (orderComm_mulVec_cartWord_singlet): combines the uniform order×order commutator with the singlet corollary to produce the three-index signed sum [ô^{(α)}, ô^{(β)}] (ô^{suf} Φ) = Σ_γ Σ_k Σ_δ (i ε_{αβγ})(i ε_{γ suf_k δ}) (ô^{suf[k ↦ δ]} Φ). Single-swap expectation identity (cartWord_swap_dotProduct_eq): the Cartesian analogue of Theorem 4.9’s orderWordProd_swap_dotProduct_eq (Bool eigenvalue telescoping). For a singlet Φ, one adjacent transposition of order-word letters expands as a signed triple sum over shorter charge-removed words: ⟨Φ, ô^{pre α β suf} Φ⟩ − ⟨Φ, ô^{pre β α suf} Φ⟩ = Σ_γ Σ_k Σ_δ (i ε_{αβγ})(i ε_{γ suf_k δ}) ⟨Φ, ô^{pre ++ suf[k ↦ δ]} Φ⟩. Equalities only; real-part band, operator-norm bound, and O(1/V) estimate are PR-3.3 (Prop 4.10 capstone).