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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.BadEvents.EllipticityBranchLow

EllipticityBranchLow #

Ported from scottnarmstrong/Superdiffusion at 7f20476385d4af418f110303085ad0740c9eba46. Module imports, support namespace and local option directives adapted for Lean Pool.

The coarse-ellipticity branch of l.bad.event.lemma at n < m #

BadEventLemmaCases.lean supplies a conditional local result for the coarse-ellipticity branch of ABK26's Lemma l.bad.event.lemma on the branch n >= m. This module supplies a conditional local result for the other branch, n < m:

lambda^{-1}_{1/8,2}(square_m; a_n)
  <= max_{z in 3^n Z^d cap square_m} lambda^{-1}_{1/8,2}(z + square_n; a_n) ,

then p.cg.ellipticity.bounds at each translate and l.maximums.Gamma.s.

The two corrections this branch runs under #

The size of the gate #

The gate above is a genuine restriction on m - n, not a constant adjustment. Two remarks fix its size.

The two conditional binders #

Main results #

References #

The frozen deterministic profile at q = 2 #

theorem Algsuperdiff.Section3.Provider.BadEvents.lowerEllipticityProfile_exponentTwo_sixteenth_le {Ccg gamma : ℝ} (hCcg : 0 < Ccg) (hgamma : gamma ≤ 1 / 16) :
lowerEllipticityProfile Ccg gamma (1 / 16) exponentTwo ≤ Ccg

At gamma <= 1/16 the frozen deterministic profile at the exponent t = 1/16 is below the frozen constant itself, which is what the manuscript's threshold 2 C_{(e.cg.ellip.lower)} needs. This is the t = 1/16 analogue of the proved lowerEllipticityProfile_exponentTwo_le.

The manuscript's own admissibility e.bad.event.admissibility, at the dimension-only constant badEventOscAdmissibleConst, implies gamma <= 1/16 (indeed gamma <= 1/32). Same derivation as the proved gamma_le_one_eighth_of_admissible, read at the exponent.

The transfer at the observable level #

ErrorComparison.lambdaSq_eighth_inv_le_two_mul_max_descendants_sixteenth is a statement about the literal Ch02.lambdaSq of a triadic coefficient family, and holds pointwise in the sample.

The observable bodies are the literals clamped at 0, so cubeLowerEllipticityInv M Q n s hs q is cubeLowerEllipticityInvLiteral M Q n s q on the source range s > 0 (cubeLowerEllipticityInv_eq_literal), and the transfer descends at every sample point. The same applies to the a.e. route of LambdaTransfer.lean.

The transfer, at the observables. Almost surely (in fact at every sample point — see the structure note above),

lambda^{-1}_{1/8,2}(square_m; a_n)
  <= 2 max_{R in descendantsAtScale Q n} lambda^{-1}_{1/16,2}(R; a_n) ,

The per-translate tail #

In the manuscript, p.cg.ellipticity.bounds at scale n, applied at the translate z + square_n, gives the weak-Orlicz bound whose tail at the level Ccg is the printed double exponential. The argument is the proved one of BadEventLemmaCases.lean, read at the translate and at the exponent.

The per-translate tail (ABK26). At each scale-n translate R, the coarse-graining input at the exponent t = 1/16 gives

P[ lambda^{-1}_{1/16,2}(R; a_n) sigmabar_{n-1} > 2 Ccg ]
  <= exp( - exp( (1/4) Ccg^{-1} E^{-2} gamma^{-1} ) ) .

The subcube cover of the failure event #

The subcube decomposition of the failure event (ABK26), almost surely: at the re-based constant 2 Ccg the printed-cube coarse-ellipticity failure event is covered by the scale-n translate events at the bare level 2 Ccg.

The branch, loss-carrying and gate-free #

The case n < m of the coarse-ellipticity branch (ABK26), with the union loss carried:

P[ lambda^{-1}_{1/8,2}(square_m; a_n) sigmabar_{n-1} > 2 . (2 Ccg) ]
  <= 3^{d(m-n)} exp( - exp( (1/4) Ccg^{-1} E^{-2} gamma^{-1} ) ) .

There is no hypothesis on m - n: the cardinality of the translate set appears in the conclusion, where the manuscript puts it into an "adjusted" constant c, which a dimension-only c cannot absorb. The passage to the printed shape is measureReal_coarseEllipticityFailure_le_of_absorb.

The constant 2 Ccg at which the failure event is read is the Ccg re-basing (gap route, G <= 2); hcg is the coarse-graining input at every translate, at the exponent t = 1/16.

The absorption of the union loss #

The logarithm of the union loss is the manuscript's own d (m - n) log 3.

The absorption of the union loss. If the entropy of the 3^{d(m-n)} translates fits under the per-translate double exponent with room T to spare, the branch is delivered at the level exp(-T).

The hypothesis hAbsorb is the inequality the manuscript's needs and does not state; by log_card_descendantsAtScale it reads

d (m - n) log 3 + T <= exp( (1/4) Ccg^{-1} E^{-2} gamma^{-1} ) .

It is a restriction on the scale separation m - n, not a constant adjustment.

The printed shape of the branch, under the explicit entropy gate. With T = exp((1/8) Ccg^{-1} E^{-2} gamma^{-1}) the conclusion is the manuscript's own display, at the dimension-only constant c = Ccg^{-1}/8 (the proved n >= m branch delivers Ccg^{-1}/4, which is stronger, so the two branches combine at Ccg^{-1}/8).

The gate is stated in the manuscript's own variables: m = Q.scale, n, and d.