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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.Diffusivity.ApproximateRecurrence.PrincipalResponseBudgetDescent

PrincipalResponseBudgetDescent #

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

Binder descriptions below are an informal inventory only, NOT a source certification; certification vocabulary is reserved for frozen source-facing declarations.

Provider: the deterministic leg of the budget of e.use.also.for.the.upper.bound #

This module supplies the two deterministic inequalities of the chain printed in ABK26, namely the passage

  bfJ(cu_n, bfAhom^{-1/2} e, bfAhom^{1/2} e; a)
    <=  mathcalE_{s,infinity,2}(cu_n; a, a_0)^2
    <=  3^{2 s (N - n)} mathcalE_{s,infinity,2}(cu_N; a, a_0)^2 ,

for an arbitrary triadic coefficient family a, at the isotropic comparator a_0 = sigma Id, on the tower of centered cubes cu_n subset cu_N. The first step is the first inequality of e.mathcalE.monotone.ordered, squared; the second is e.bound.one.cube.by.mathcalE, in its per-descendant form, also squared.

Everything below is pointwise in the coefficient field: no law, no expectation, no induction state. The probabilistic half of the budget is the second moment of mathcalE, which is not touched here.

The probe #

What is proved first is that this pair is literally an element of CoarseGraining's normalized block-response value set Ch02.normalizedBlockResponseValueSet of the comparator Observable.isotropicComparatorMatrix sigma, whose doubled unit witness is Sum.elim e_1 e_2; that is exactly the sense in which mathcalE maximizes over the same probe family. The manuscript's normalization |e| = 1 is the hypothesis hE : blockVecDot = 1, which ...PrincipalResponseSwitch.exists_blockVecDot_self_eq_one shows is satisfiable.

The exponent #

The third line of the manuscript's chain carries the factor 3^{t(m-h-n)} in front of the second moment of mathcalE. Composing the first inequality of e.mathcalE.monotone.ordered (which squares) with e.bound.one.cube.by.mathcalE (stated for mathcalE itself) produces 3^{2 t (m-h-n)}, not 3^{t(m-h-n)}. Under the manuscript's own scale choice both factors are absolute constants, so nothing downstream moves.

Main results #

References #

Real-power bookkeeping #

The tex probe is a probe of mathcal E #

ABK26 against d.mathcal.E. The pair (bfAhom^{-1/2} e, bfAhom^{1/2} e) at the isotropic comparator sigma Id realizes the doubled response bfJ as an element of the normalized block-response value set whose supremum mathcalE maximizes. The doubled witness is Sum.elim e_1 e_2, whose squared Euclidean norm is the manuscript's |e|^2.

The first inequality of e.mathcalE.monotone.ordered, squared #

e.bound.one.cube.by.mathcalE on the centered tower #

The deterministic leg #

The deterministic leg of the budget of ABK26.

At the annealed probe of ABK26, on the centered tower cu_n subset cu_N,

  bfJ(cu_n, bfAhom^{-1/2} e, bfAhom^{1/2} e; a)
    <=  3^{2 s (N-n)} mathcalE_{s,infinity,2}(cu_N; a, sigma Id)^2 .

No law and no induction state occur; the remaining half of the manuscript's chain is the second moment of the right-hand side.