Coarse-graining support: Support.Book.Ch05.Theorems.Section57.BadScalePairCollapse #
Imported from the Apache-2.0 CoarseGraining development at commit
c7ddd76c08ade64fed1b8d2ca51be14dfee8deb4.
Deterministic fixed-pair exponent collapse #
This file contains the deterministic lower bounds on the raw tail parameters
from BadScalePairTwoBranch. These are the first two manuscript-facing
collapses: the localized top range gives the b*q concentration scale, and the
crude bottom range gives the t*q discount scale.
In the localized range with q ≤ n, the raw high-branch tail parameter
dominates the manuscript b*q scale, up to a summable geometric weight in
m-q.
In the crude bottom range, the raw crude tail parameter dominates the
manuscript t*q scale, up to a summable geometric weight in m-q.
In the mixed range n <= q where the localized scale is available, the
localized tail parameter has the exact interpolating exponent between the
concentration gain at scale n and the discount gain from q - n. This is
kept separate from theorem-facing tails so that no weakened leading exponent is
exposed as a public endpoint.
In the bottom range n <= q, the crude tail parameter has the exact
discount exponent. This lemma does not require the complementary condition
n <= ell; it is the crude half of the mixed-branch comparison.
Direct localized estimate for the mixed bottom branch.
The conclusion keeps the exact interpolating exponent. This is stronger than the two-branch soft estimate when the localized branch is the better one, and it is used later only before the final endpoint collapse.
Direct crude estimate for the mixed bottom branch.
This is independent of the selected localized scale: the event is a subset of the bad-pair event, and the unit-scale crude input supplies the discount parameter in the bottom range.
Exact probability-level estimate for the mixed bottom localized branch.
This is the delicate n <= q and ell < n region. The conclusion deliberately
keeps the two honest raw mechanisms visible: the localized interpolation scale
and the crude discount scale. The theorem-facing bad-scale tail must still
collapse these without turning the localized interpolation term into a leading
c*q estimate.