ScalingStacks

Example 3.2 . [028M]

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Example 3.2.

Let X={y=0}∪{y=1}⊂ℂ2X=\{y=0\}\cup\{y=1\}\subset{\mathbb{C}}^{2} and η∈ℒ⁡(X)\eta\in{\mathcal{L}}(X), where

η⁡(z)={ρ⁡(1,z),if​z=(x,0),ρ⁡(1,z)+1,if​z=(x,1).\eta(z)=\left\{\begin{array}[]{ll}\rho(1,z),\;\;\;\;\;\;\;{\rm if}\;z=(x,0),\\ \rho(1,z)+1,\;{\rm if}\;z=(x,1).\end{array}\right.

The function η~\widetilde{\eta} is not ω\omega-psh on X¯={y=0}∪{y=t}\overline{X}=\{y=0\}\cup\{y=t\}, hence η\eta does not have an extension in ℒ⁡(ℂ2){\mathcal{L}}({\mathbb{C}}^{2}). Indeed, the maximum principle is violated along {y=0}\{y=0\} near the point a=[0:1:0]a=[0:1:0], since η~([t:1:0])=0\widetilde{\eta}([t:1:0])=0 for t≠0t\neq 0, while η~([t:1:t])=1\widetilde{\eta}([t:1:t])=1.

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