ScalingStacks

Proof. [02ED]

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Proof.

We first show that (φj)(\varphi_{j}) converges to φ\varphi in L1​(μ)L^{1}(\mu). Observe that the sequence (φj)(\varphi_{j}) is uniformly bounded: this follows from Theorem 2.1 since (ω+d​dc​φj)n(\omega+dd^{c}\varphi_{j})^{n} satisfies ℋ⁡(α,Aj,ω){\mathcal{H}}(\alpha,A_{j},\omega), where Aj=et​supXψj−cψj​A≤et​Mμ​AA_{j}=e^{t\sup_{X}\psi_{j}-c_{\psi_{j}}}A\leq e^{tM_{\mu}}A is bounded from above. It follows then from standard arguments that ∫Xφj​𝑑μ→∫Xφ​𝑑μ\int_{X}\varphi_{j}d\mu\rightarrow\int_{X}\varphi d\mu (see e.g. the proof of lemma 5.2 in [Ce]).

Fix ε>0\varepsilon>0 and let GG be an open set of XX such that φ\varphi is continuous on X∖GX\setminus G and C​a​pω​(G)≤εCap_{\omega}(G)\leq\varepsilon (see corollary 3.8 in [GZ 1]). By Hartogs’ lemma, φj≤φ+ε\varphi_{j}\leq\varphi+\varepsilon on the compact set X∖GX\setminus G, if j≥jεj\geq j_{\varepsilon}. Observe that

∫X∖G|φ−φj|​𝑑μ≤2​ε+∫X∖G[φ−φj]​𝑑μ≤3​ε,\int_{X\setminus G}|\varphi-\varphi_{j}|d\mu\leq 2\varepsilon+\int_{X\setminus G}[\varphi-\varphi_{j}]d\mu\leq 3\varepsilon,

if j≥jε′j\geq j^{\prime}_{\varepsilon}. O the other hand since μ\mu satisfies ℋ⁡(α,A,ω){\mathcal{H}}(\alpha,A,\omega), we get

∫G|φ−φj|​𝑑μ≤2​M​μ​(G)≤2​M​A​ε1+α,\int_{G}|\varphi-\varphi_{j}|d\mu\leq 2M\mu(G)\leq 2MA\varepsilon^{1+\alpha},

where M=supj‖φj‖L∞​(X)M=\sup_{j}||\varphi_{j}||_{L^{\infty}(X)}. This shows that ‖φ−φj‖L1​(μ)→0||\varphi-\varphi_{j}||_{L^{1}(\mu)}\rightarrow 0.

The proof for (et​ψj)(e^{t\psi_{j}}) is similar: it suffices to note that the functions uj:=et​ψj−t​supXψju_{j}:=e^{t\psi_{j}-t\sup_{X}\psi_{j}} are ω\omega-psh and uniformly bounded. One can then apply the rest of the argument. ∎

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