ScalingStacks

Proof. [01C5]

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Proof.

Fix u∈PSH⁡(X,ω)u\in\PSH(X,\omega) with 0≤u≤10\leq u\leq 1 and set ψt:=(1−t)​ψ+t​u\psi_{t}:=(1-t)\psi+tu. We have

{φ<ψ}⊆{φ<ψt}⊆{φ<(1−t)ψ+t}.\{\varphi<\psi\}\subseteq\{\varphi<\psi_{t}\}\subseteq\{\varphi<(1-t)\psi+t\}.

since ψ≤0\psi\leq 0. Now MA⁡(ψt)≥tn​MA⁡(u)\MA(\psi_{t})\geq t^{n}\MA(u) by (3.1), so

tn∫{φ<ψ}MA(u)≤∫{φ<ψ}MA(ψt)≤∫{φ<ψt}MA(ψt)≤∫{φ<ψt}MA(φ)≤∫{φ<(1−t)ψ+t}MA(φ),t^{n}\int_{\{\varphi<\psi\}}\MA(u)\leq\int_{\{\varphi<\psi\}}\MA(\psi_{t})\leq\int_{\{\varphi<\psi_{t}\}}\MA(\psi_{t})\\ \leq\int_{\{\varphi<\psi_{t}\}}\MA(\varphi)\leq\int_{\{\varphi<(1-t)\psi+t\}}\MA(\varphi),

where the third inequality follows from the comparison principle (6.7). Taking the supremum over uu completes the proof. ∎

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