Paper-scale L² good event #
This file packages the quantitative last step of paper §3.4, Step 1.
The analytic estimates (3.31)--(3.32) must supply a factorized
parametrix Q and its two operator remainders. On the paper-scale
event
‖Q‖ ≤ ε⁻¹⁴, ‖Rleft‖ + ‖Rright‖ ≤ ε²⁸,
the two-sided algebra from L2ParametrixInverse.lean constructs the
inverse of 1 - G M. Since ‖G‖ ≤ 1, its inverse Green operator
differs from QG by at most ε¹² for sufficiently small positive
ε.
The event is kept separate from its probabilistic estimate: the moment bounds in P-3.5/P-err provide the hypotheses of the Markov lemmas below.
Fourier matrix coefficients and the (3.30) bound #
The (3.23)-signed Fourier matrix coefficient of a bounded operator.
The minus sign on the left mode is the one forced by the paper's
non-conjugated Fourier kernel convention.
Equations
- Anderson4D.torusFourierMatrixCoeff A α β = inner ℂ (Anderson4D.torusFourierBasis (-α)) (A (Anderson4D.torusFourierBasis β))
Instances For
A bounded operator is controlled by the square-sum of its values on the torus Fourier basis. This is the Hilbert-space core of (3.30), proved directly because no named Hilbert--Schmidt API is required.
Weighted Fourier double-sum form of (3.30). Any nonnegative weight
bounded below by one may be used; the paper later instantiates this with
ε⁻⁸ ⟨ε²(α+β)⟩⁶. The two summability hypotheses are the honest
non-junk conditions for the nested real tsum.
The exact weight printed in paper (3.30):
ε⁻⁸ ⟨ε²(α+β)⟩⁶. The Japanese bracket is expanded as
⟨t⟩⁶ = (1 + ‖t‖²)³, avoiding fractional powers.
Equations
Instances For
Exact paper-weight specialization of (3.30).
Product-index version of the exact paper-weight bound. This is the convenient form for Tonelli: one summability hypothesis replaces the two nested non-junk hypotheses.
Tonelli form of the expected (3.30) estimate. It needs only
termwise measurability and almost-everywhere summability; no integrability
of the full random double sum is assumed in advance.
Numerical closure of the Tonelli estimate from termwise weighted
second-moment bounds. This is the exact adapter between P-3.5b and
P-L2: all probability is confined to hterm, while the remaining
obligation is a deterministic summable majorant.
Turn an ordinary second-moment bound into the weighted lintegral
bound consumed by lintegral_operatorNormSq_le_of_weightedMomentBound.
The scalar c records normalization changes such as the paper-volume
factor in the kernel/operator ledger.
The concrete orderwise P-3.5b to P-L2 bridge #
An order-m bounded random operator realizes the physical random
kernel P_m when its Fourier matrix coefficients equal the paper
coefficients almost surely, including the inverse torus-volume
normalization forced by the use of probability Haar measure in
TorusL2.
Almost-sure equality is essential here: the noise model specifies random variables only up to null sets, and P-3.5b yields simultaneous square summability only almost surely. Requiring the equality at every sample would add a non-probabilistic regularity hypothesis not present in the paper.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Deterministic weighted moment majorant after translating the paper-normalized coefficient to the probability-Haar operator coefficient.
Equations
- One or more equations did not get rendered due to their size.
Instances For
P-3.5b gives both measurability and the weighted term estimate needed by the Tonelli form of (3.30), with every normalization factor visible.
Orderwise P-3.5b to P-L2 closure. After the deterministic weighted
majorant is summable and the realized coefficient square-sum is
non-junk almost surely, the expected L² → L² norm is bounded by the
sum of the explicit (3.24) × (3.30) majorant.
Real-valued expectation form of the preceding theorem.
Expectation adapter for (3.30). Once both nonnegative sides are integrable, the pointwise Fourier double-sum bound passes directly to expectation.
The paper-scale remainder threshold implies the half-ball event used by the Banach-algebra inversion theorem.
Membership in the paper-scale event constructs the factorized Anderson inverse.
Quantitative form of (3.33) for the factorized bounded-operator realization.
The elementary small-ε hypotheses needed by the preceding
theorem follow from the convenient range 0 < ε ≤ 1/2.
First-moment control of the event #
A thresholded first moment bounds the real measure of the corresponding norm-bad event.
Markov and the union bound control failure of the two paper-scale thresholds. The remainder sum is treated as one nonnegative random variable, exactly as in (3.32).
Substituting the two estimates in (3.32) gives the advertised
O(ε²) exceptional-event probability, with the explicit union-bound
constant 2.