Documentation

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

BadEventScaleShiftBridge #

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

The scale-shift bridge from the frozen bad-event estimate to the dimension floor #

Algsuperdiff.Frozen.Section3.bad_event_estimate publishes only 1 ≤ Ccg about its existential witness, while the Section 3.4 good half needs (d : ℝ) ^ 6 ≤ Ccg at the same constant, and goodLocalEvent is not monotone in that constant: its threshold

goodLocalThreshold M C m n = (1/2) * C⁻¹ * 3 ^ (-(1/2) * scaleGapPos m n) * sigmabar

is antitone in C, so the sensitivity clause tightens and the ellipticity clause loosens as C grows. An earlier disclosure in this cone concluded from this that no transfer exists. That conclusion was wrong, and this module proves the transfer.

The mechanism #

The constant can be traded against the cube scale, because the oscillation gauge is more strongly scale-weighted than the threshold. At a common centre (cubeBasePoint (originCube d ell) = 0 for every ell),

cubeOscGauge (originCube d j) h
  = max (3 ^ (2 j) * ‖∇²h‖_{L∞(cu_j)}) (3 ^ j * ‖∇h‖_{L∞(cu_j)}) ,

so enlarging the cube from scale m to mu multiplies the sup upwards but the weights by 3 ^ (-2 (mu - m)) resp. 3 ^ (-(mu - m)), giving

whereas the threshold only gains 3 ^ ((mu - m)/2). With mu = m + 2k the two weights combine to an exact identity

whence the two clause inclusions

and their combination

The dimension shift #

badEventScaleShiftExp d := 6 * d is dimension-only and elementary: d < 3 ^ d gives (d : ℝ) ^ 6 ≤ 3 ^ (6 * d), which is all the floor (d : ℝ) ^ 6 ≤ Cbase needs. No logarithm and no ceiling occurs.

Scope #

This module proves the geometric core of the bridge, verified in Lean. The consuming step -- applying Algsuperdiff.Frozen.Section3.bad_event_estimate twice at the same translate triadicCubeShift R, once at the cube scale R.scale and once at R.scale + 2 * badEventScaleShiftExp d, and combining by the union bound -- is proved in Provider.Diffusivity.ApproximateRecurrence.BadEventFrozenApplication, which is what the Section 3.4 bad-event leg consumes.

The clause inclusions are therefore stated in the full regime m ≤ n (goodLocalThreshold_scaleShift_le, goodLocalSensitivity_scaleShift_subset_le, goodLocalEvent_inter_subset_scaleShift_le), not only when the enlarged scale m + 2 k still sits below n: the Section 3.4 grid is indexed by a free recurrence multiplier and offers no headroom at its degenerate end, so the consumer discharges the two frozen n < m gates on their own terms instead. The exact threshold identity at the original gate m + 2 k ≤ n is kept as goodLocalThreshold_scaleShift.

References #

The gauge at an origin cube #

(L1) Cube-scale monotonicity of the oscillation gauge at a common centre. Enlarging the origin cube from scale m to mu ≥ m gains the factor 3 ^ (m - mu) ≤ 1: the sup can only grow, but the gauge weights 3 ^ (2 j) and 3 ^ j grow strictly faster. This is the lemma that makes the constant of e.good.local.events tradeable against the cube scale.

The threshold identity and the two clause inclusions #

theorem Algsuperdiff.Section3.Provider.Diffusivity.ApproximateRecurrence.goodLocalThreshold_scaleShift {d : ℕ} (M : ABKModel d) {C : ℝ} (hC : 0 < C) (m n : ℤ) (k : ℕ) (hmn : m + 2 * ↑k ≤ n) :
3 ^ (m - (m + 2 * ↑k)) * BadEvents.goodLocalThreshold M (2 * C) (m + 2 * ↑k) n = BadEvents.goodLocalThreshold M (2 * 3 ^ k * C) m n

The exact threshold identity behind the scale shift: the cube-scale gain of the gauge and the loss of the threshold combine to the constant 3 ^ k.

theorem Algsuperdiff.Section3.Provider.Diffusivity.ApproximateRecurrence.goodLocalThreshold_scaleShift_le {d : ℕ} (M : ABKModel d) {C : ℝ} (hC : 0 < C) (m n : ℤ) (k : ℕ) (hmn : m ≤ n) :
3 ^ (m - (m + 2 * ↑k)) * BadEvents.goodLocalThreshold M (2 * C) (m + 2 * ↑k) n ≤ BadEvents.goodLocalThreshold M (2 * 3 ^ k * C) m n

The threshold scale shift as an inequality, in the full regime m ≤ n.

The exact identity of goodLocalThreshold_scaleShift needs the enlarged scale m + 2 k to sit below the field scale n. When it does not, the enlarged threshold saturates at its own gap 0 while the original one keeps the factor 3 ^ (-(1/2)(n - m)), and the shifted comparison survives as an inequality because n - m ≤ 2 k on that branch. Only this inequality is used downstream, so the bridge applies at every cube of the Section 3.4 grid, not only at those with 2 k scales of headroom.

The scale shift on the sensitivity clause. Membership at the enlarged cube and the small constant implies membership at the original cube and the constant multiplied by 3 ^ k. Stated in the full regime m ≤ n, through goodLocalThreshold_scaleShift_le.

The ellipticity clause only grows when the constant grows, because the threshold it lower-bounds is antitone in the constant.

The scale-shift bridge at the level of the good local event. The two frozen-reachable events at the small constant, one at the cube scale and one at the enlarged scale, together imply the event at the enlarged constant. Stated in the full regime m ≤ n: no headroom between the enlarged scale and the field scale is required.

The dimension-only scale shift #

The dimension-only scale shift: 3 ^ (6 d) clears the floor (d : ℝ) ^ 6 by the elementary d < 3 ^ d. No logarithm and no ceiling occurs.

Equations
Instances For