ScalingStacks

Definition 2.28 . [02JA]

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Definition 2.28.

Let L¯i{\overline{L}}_{i}, i=0,…,d−1i=0,\dots,d-1, be line bundles on XX equipped with algebraic metrics. For each ii, choose a model (𝒳i,ℒi,ei)(\mathcal{X}_{i},\mathcal{L}_{i},e_{i}) that realizes the metric of L¯i{\overline{L}}_{i}. We can assume without loss of generality that the models 𝒳i\mathcal{X}_{i} agree with a common model 𝒳\mathcal{X}. Let YY be a dd-dimensional subvariety of XX and YanY^{{\text{\rm an}}} its analytification. Let 𝒴⊂𝒳\mathcal{Y}\subset\mathcal{X} be the closure of YY, 𝒴~{\widetilde{\mathcal{Y}}} be its normalization, 𝒴~o{\widetilde{{\mathcal{Y}}}}_{o} its special fibre, and 𝒴~o(0){\widetilde{{\mathcal{Y}}}}_{o}^{(0)} the set of irreducible components of this special fibre. For each V∈𝒴~o(0)V\in{\widetilde{{\mathcal{Y}}}}_{o}^{(0)}, consider the point ξV∈Yan\xi_{V}\in Y^{{\text{\rm an}}} defined by (2.15). Let δξV\delta_{\xi_{V}} be the Dirac delta measure on XanX^{{\text{\rm an}}} supported on ξV\xi_{V}. We define a discrete signed measure on XanX^{{\text{\rm an}}} by

(2.29) c1⁡(L¯0)∧⋯∧c1⁡(L¯d−1)∧δY=∑V∈𝒴~o(0)ordV⁡(ϖ)​degℒ0,…,ℒd−1⁡(V)e0​…​ed−1​δξV.\operatorname{c}_{1}({\overline{L}}_{0})\land\dots\land\operatorname{c}_{1}({\overline{L}}_{d-1})\land\delta_{Y}=\sum_{V\in{\widetilde{{\mathcal{Y}}}}_{o}^{(0)}}{\operatorname{ord}}_{V}(\varpi)\frac{\deg_{\mathcal{L}_{0},\dots,\mathcal{L}_{d-1}}(V)}{e_{0}\dots e_{d-1}}\delta_{\xi_{V}}.

This notion extends by linearity to the group of dd-dimensional cycles of XX.

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