Mass estimates for decomposition cleanup #
The cleanup operations delete local atoms. These finite-sum estimates keep track of the lost mass and of the resulting deterioration of thickness.
theorem
EGZ.IsThickAlong.of_pruning
{p d : ℕ}
[NeZero p]
{w w' : FpCoord p d → ℕ}
{ξ : FpCoord p d →ᵃ[ZMod p] ZMod p}
{K : ℕ}
{δ α ε M : ℝ}
(hthick : IsThickAlong w ξ K δ)
(hle : w' ≤ w)
(hε : 0 < ε)
(hα : 0 ≤ α)
(hlarge : ε * M ≤ ↑(natMass w))
(hloss : ↑(natMass w) - ↑(natMass w') ≤ α * M)
(hδ : 0 ≤ δ - α / ε)
:
IsThickAlong w' ξ K (δ - α / ε)
Deleting at most α M mass from a weight of mass at least ε M
degrades thickness by at most α / ε. The strict inequality agrees with
the definition of thickness as the negation of thinness.