Coordinate-sweep contraction constants: selected source audit

The selected trace solution has an existential universal sweep threshold, but this review has not extracted a useful numerical value. The hashed reading record distinguishes these selected module excerpts from a complete imported-proof review. The source commit remains fd4aeeb2ee4fc729c18d98444fed42fd0529eeeb. No Lean, Comparator or independent kernel ran.

TraceModel.lean imports Harmonic.Main, inside OAI.ThorpNine.Harmonic. The parallel Casimir module contains similar names but is not the selected import for this path. TraceDecay.uniform_nonconstant_decay takes positive level/dimension contraction coefficients a,b and chooses m>=max(14/a,2/b), then u=2m. The regular trace conclusion uses P=2u. This chain provides a proof witness for existence; the preceding finite four-card calibration does not choose the universal witness.

In Harmonic/Main lines 415–478, the eventual level coefficient combines a spectral coefficient and a dimension coefficient. An eventual threshold D is obtained, and the finite part takes a positive lower bound of f(d)=-log(blockGap(d))/2^d over d<D. The resulting all-d coefficient is the minimum of the eventual and finite bounds. In lines 1087–1138, the dimension contraction similarly uses f(d)=-log(blockGap(d))/(1+log((2^d)!)) and a finite positive minimum. Neither numerical D nor the underlying spectral coefficients were selected in this review.

Harmonic/AverageMap lines 271–292 defines a finite convolution minorant. Its exponent is classically chosen from existence of a positive convolution power; its mass is the full-group size times the minimum mass of that selected power. Lines 463–480 give blockGap=1-mass/(2*2^exponent), and lines 687–694 instantiate it for the palindrome shuffle. This is more information than merely saying the gap is positive, but evaluating a literal full-group minimum is a separate finite construction with factorial-sized state space. An explicit sharper minorant or spectral estimate could be an engineering bridge; it is not supplied by these references.

The product decision remains conditional: do not advertise a source-certified sweep schedule from the tiny fixtures or a hand-picked P. Next inspect the spectral-regime numerical dependencies, and consider an exact four-card palindrome minorant as a finite calibration only. A changed proof with quantitative witnesses, a validated independent-bit backend and correspondence to an actual implementation remain separate obligations. Framework dossier.