Change can only cross the boundary
A projector Π marks what is presently occupied; a generator Ω is what tries to change it. The part of the change that matters is F(Ω,Π) = (I−Π)ΩΠ + ΠΩ(I−Π): it lives only between the occupied subspace and its complement, its trace is zero, and it vanishes exactly when [Ω,Π] = 0. Turn up the cross-coupling and watch weight leave the occupied block.
The same footprint, a different memory
Write the generator in blocks, H = [[A, B], [B†, D]], retained sector first. Eliminating the hidden sector leaves a memory kernel K(t) = B e−itD B† and a source term. Its value at zero time, K(0) = BB†, is fixed by the coupling alone, and it is exactly what redistribution measures. Change the hidden generator D and keep B: the footprint stays put while the memory and the retained trajectory change.
Curvature is paid out of the metric
For any two tangents at a projector, |Ω(V,W)| ≤ 2√(g(V,V)g(W,W) − g(V,W)²). Equality holds exactly when the two projected tangent vectors are complex-parallel. Two bands force it, because the complement of a rank-one band is one complex line. Beyond two bands a symmetry can supply it: the kagome lattice at bond phase π/6 saturates on its outer bands with curvature present, and a generic phase leaves slack.
The eigenvalue forgets the direction; the phase keeps it
On the flat torus the twisted operator has paired eigenvalues ±2π√((m+α)²+(n+β)²). Its positive projector carries a phase eiΦ = Z/|Z| that the eigenvalue cannot see. Carry the holonomy around a loop: the magnitude only tells you how far you are from the zero, while the phase records how many times you went around it.
A neutral point does not make the path free
The potential U(T) = (T² − a²)² + ε has neutral sectors, yet every path from −aI to aI pays O(γ) = ∫(1/N) Tr U dt > 2aε. Squeezing the crossing into a narrow window brings the cost down toward the floor, never below it. A path that moves no faster than one unit per unit time has no such freedom: it must be T = tI, and it pays 16a⁵/15 + 2aε.
Joining two regions costs no more than the parts
Glue patches A and B through the interface block R_M = [[R_A, ε],[ε†, R_B]]. The Schur step gives O(A∪B) = O(A) + O(B) + Δ with Δ = Σ log(1 − μ_k) ≤ 0: obstruction that each side carried on its own is partly carried by the other, and at the seam it cancels. A skew-coupled block, run as a control, gives the opposite sign.
An integer that needs a large enough failure to commute
Replace the two holonomy numbers by two unitaries U, V and read the relator R = UVU†V†. Its determinant is one, so its eigenphases add to a whole number of turns: the winding w. The branch guard g is the distance of the spectrum from −1, the defect δ how far R is from the identity. Every pair obeys δ + g² ≤ 4, and a nonzero winding needs δ ≥ 16/d².
The record can only step where the polynomial meets the circle
For a knot with Seifert matrix V, the signature of (1−ω)V + (1−ω̄)Vᵀ is an integer step function of ω = e2πiα. It can step only at unit-circle roots of the Alexander polynomial, and a root is a possible step, not a forced one: the square knot has double roots on the circle and never steps. Mirror image reverses the signature, so an amphichiral knot such as the figure-eight carries zero everywhere.
Continuation runs on the A-polynomial
Admissible trajectories on the figure-eight knot complement live on the zero set of A(L,M) = L²M⁴ + L(−M⁸ + M⁶ + 2M⁴ + M² − 1) + M⁴. On the unitary slice, M = eiθ, the longitude obeys L² + 2sL + 1 = 0 with s = 1 + cos 2θ − cos 4θ, and it stays on the circle exactly where |s| ≤ 1. Moving along the curve, the meridian and longitude are geared by the Jacobian ratio u̇ = −(J_L/J_M) v̇.
Symmetry is broken by a seed, then amplified
A statically amphichiral substrate carries a zero record, so a persistent distinction needs a chiral substrate or a trajectory that breaks the mirror symmetry. But a mirror-symmetric start under mirror-equivariant transport stays symmetric for all time. An instability amplifies a seed; it does not create one. Drop three balls in the same double well: one exactly at the symmetric point, and two with seeds of opposite sign.
Neutral, chiral, or composite
A boundary flow either has no global winding vector (an open flow), or it carries w = (w_α, w_β) ∈ ℤ². Every such vector is exactly one of three kinds: zero (a neutral loop), primitive with gcd = 1 (a chiral loop), or a composite k·w₀. The trichotomy is the statement that composites split into primitive loops under perturbation. That selection needs a stress functional, which the paper leaves open.
The pipeline on a measured band
Yi and colleagues reconstructed the Bloch states of a two-dimensional Raman lattice of ⁸⁷Rb condensates. Their calibrated band is h = (2t_so sin q_y, 2t_so sin q_x, δ/2 − 2t₀(cos q_x + cos q_y)) with t₀ = 0.09, t_so = −0.05. On it the winding currency, the saturated bound and the rigidity of the declared operator h·σ are computed here from the published parameters. This is a calculation on a published model, not new laboratory data.
Rigidity bends a path that crosses a wall
Give rigidity a dynamical role with the scalar action S = ∫(½R|q̇|² − V)dτ. Across a planar interface the tangential momentum R v sin θ is conserved and so is the energy, so R₁(E−V₁)sin²θ₁ = R₂(E−V₂)sin²θ₂. Beyond the critical angle the path turns back. With R = 1/(s² + η) the transmitted angle never collapses to zero at fixed η.
From samples to a projector path
Form a covariance, eigendecompose it, keep the top k directions as a projector Π_k, and follow that projector as a setting moves. Principal angles, persistence P = Tr(Π_k(t)Π_k(t+Δt)) and the effective dimension D_C = 1/IPR are functionals of the projector path alone. The gap at the cut sets how easily the projector turns: its compliance is 1/γ_k. The samples here are synthetic draws from a declared model, not instrument data.
Individual projectors fail; the cluster does not
Take H(γ) = σ_x + iγσ_z. Its eigenvalues ±√(1−γ²) collide at γ = 1, and each rank-one projector blows up on the way in. A contour around both eigenvalues gives the Riesz projector of the pair, and it stays exactly the identity, with trace two, straight through the collision.
Claim ledger
Grades: [T] exact or derived; [V] verified by a gated check; [C] cited from the literature; [D] data-reported, pending its protocol; [H] hypothesis, protocol or interpretation. Lean: machine-checked in the upg-lean repository (forty theorems in eight modules).
| Claim | Where | Grade |
|---|---|---|
| F(Ω,Π) is traceless, off-diagonal, and vanishes exactly when [Ω,Π] = 0 | Theorems 1.2–1.3 | T+V |
| ‖F‖² = ‖[H,Π]‖² = 2 Tr K(0): redistribution is the zero-time footprint of the memory kernel | Proposition 1.5 | T+V, Lean |
| K(0) fixes the footprint, not the memory: same B, different D gives different K(t) | Section 1, B.9 | T+V |
| Saturation of the metric–curvature bound exactly for complex-parallel projected tangents | Section 2 | T |
| Kagome outer bands at bond phase π/6 saturate with curvature present | Section 2, B.9 | V |
| Phase transport on the torus anchor gives integer windings 0, +1, +2 | Theorem 4.1 | T+V |
| Every path pays O(γ) > 2aε; the floor is sharp; normalized paths pay 16a⁵/15 + 2aε | Theorem 4.2 | T+V |
| Gluing is subadditive: Δ = Σ log(1 − μ_k) ≤ 0 | Theorem 4.3 | T under Assumption 1 |
| The seam is a discount | Section 4.3 | H |
| w ∈ ℤ, |w| ≤ ⌊(d−1)/2⌋; δ + g² ≤ 4; |w| ≤ (d/4)√δ with sharp constant ¼ | Theorems 4.5–4.8, Prop. 4.9 | T+V |
| Bott index equals the Chern number under short-range, gapped hypotheses | Section 4.4 | C |
| A-polynomial of the figure-eight knot | Equation (12) | C |
| Jacobian gearing u̇ = −(J_L/J_M)v̇ and the interaction field | Section 5.2 | T |
| An amphichiral knot carries σ ≡ 0; distinction needs a chiral substrate or a symmetry-breaking trajectory | Corollary 5.1 | T |
| The transport field amplifies a seed on the 4₁ laboratory | Section 5.3 | H |
| Every winding vector is neutral, primitive or composite | Theorem 5.4 | T |
| Composites split under perturbation; the stress functional is not yet fixed | Section 5.6 | H |
| Knot complements realize the rigidity class; the signature steps only at unit-circle Alexander roots | Theorem 5.5 | T |
| Seifert substrates excluded | Lemma 5.7 | C |
| R_η = 1/(σ_min(A_intr)² + η) ≤ 1/η; the gap sets compliance, not rigidity | Section 6.1 | T+V |
| Rigidity value on the transmon covariance | Section 6.1 | open: A_intr to be declared |
| |Ω| ≤ 2√(g(V,V)g(W,W) − g(V,W)²) | Theorem 6.1 | T+V |
| R₁(E−V₁)sin²θ₁ = R₂(E−V₂)sin²θ₂ under the scalar action | Proposition 6.2 | T given H |
| Refraction angle 14.22° in the window [14.21°, 14.23°] | Section 6.4 | D, pending the split protocol |
| Published Raman-lattice band: Chern −0.99931 against −1.00 ± 0.02; saturation; vol_g = 1.145 | Section 6.5 | C+V |
| Friction shield: suppressed antisymmetric correlations | Section 6.7 | D+H |
| Khovanov Laplacian: ker Δ ≅ Kh in each bidegree | Section 7 | T |
| Alignment of the non-harmonic spectrum with continuum gradients | Section 7 | H |
| Riesz projectors are locally Lipschitz: ‖Π′ − Π‖ ≤ K_Γ ε | Theorem 8.1 | T |