ScalingStacks

Proof. [01ZG]

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Proof.

Put δ′=δ/3\delta^{\prime}=\delta/3. Then for x∈B2​(p)x\in B_{2}(p), there are at most N⁡(v,δ)=C⁡(v)​δ−1N({\rm v},\delta)=C({\rm v})\delta^{-1} scales α\alpha for which

|𝒱rα​(x)−𝒱rα+1​(x)|>δ3.\displaystyle\Big|\mathcal{V}_{r_{\alpha}}(x)-\mathcal{V}_{r_{\alpha+1}}(x)\Big|>\frac{\delta}{3}\,. (8.16)

Hence, there are at most 3​N3N elements α∈ℕ\alpha\in\mathds{N} such that

|𝒱rβ​(x)−𝒱rβ+1​(x)|>δ3,\displaystyle\Big|\mathcal{V}_{r_{\beta}}(x)-\mathcal{V}_{r_{\beta+1}}(x)\Big|>\frac{\delta}{3}\,, (8.17)

for some β∈{α−1,α,α+1}\beta\in\{\alpha-1,\alpha,\alpha+1\}. Therefore, for all other α\alpha, we must have

|𝒱4​rα​(x)−𝒱rα/4​(x)|<δ,\displaystyle\Big|\mathcal{V}_{4r_{\alpha}}(x)-\mathcal{V}_{r_{\alpha}/4}(x)\Big|<\delta\,, (8.18)

which proves the corollary. ∎

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