ScalingStacks

Example 7.29 . [02XS]

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Example 7.29.

Let π’ͺ⁑(1){\mathcal{O}}(1) be the universal line bundle of β„™n\mathbb{P}^{n}. The Fubini-Study metric of π’ͺ​(1)an{\mathcal{O}}(1)^{{\text{\rm an}}} corresponds to the case of the standard simplex, β„“i​(x)=xi\ell_{i}(x)=x_{i}, i=1,…,ni=1,\dots,n and β„“n+1​(x)=1βˆ’βˆ‘i=1nxi\ell_{n+1}(x)=1-\sum_{i=1}^{n}x_{i} and the choice ci=1/2c_{i}=1/2 for all ii. Hence we recover from (7.28) the well known expression for the height of β„™n\mathbb{P}^{n} with respect to the Fubini-Study metric in [BGS94, Lemma 3.3.1]:

hπ’ͺ⁑(1)¯⁑(β„™n)=n+12β€‹βˆ‘j=2n+11j.\operatorname{h}_{{\overline{{\mathcal{O}}(1)}}}(\mathbb{P}^{n})=\frac{n+1}{2}\sum_{j=2}^{n+1}\frac{1}{j}.

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