ScalingStacks

3.2. The Chambert-Loir measure [01AB]

Original official author HTML, exact retained edition. Historical TeX conversion verdicts remain unchanged. Cited-edition alignment and mathematical self-containment are not assessed.

Complete original source context · Original author HTML

3.2. The Chambert-Loir measure

We follow the notation and terminology of §2.6. Consider an ample line bundle LL on XX and equip LL with a model metric ∥⋅∥\|\cdot\|. Any continuous metric on LL is then of the form ∥⋅∥e−φ\|\cdot\|\,e^{-\varphi} where φ∈C0​(X)\varphi\in C^{0}(X). Recall that this metric is semipositive iff the function φ\varphi is θ\theta-psh, where θ:=c1(L,∥⋅∥)\theta:=c_{1}(L,\|\cdot\|). In this case, set

c1(L,∥⋅∥e−φ)n:=(θ+ddcφ)n,c_{1}(L,\|\cdot\|e^{-\varphi})^{n}:=(\theta+dd^{c}\varphi)^{n},

where the right hand side is the positive Radon measure in Theorem 3.1.

This is the same measure as the one defined by Chambert-Loir in [CL06]. Indeed, this is certainly true when φ\varphi is a model function, as seen by comparing (2.2) and [CL06, Définition 2.4]. In general, Corollary 2.12 yields a sequence (φm)m=1∞(\varphi_{m})_{m=1}^{\infty} of θ\theta-psh model functions converging uniformly to φ\varphi on XX. The measure μ\mu associated to (L,∥⋅∥e−φ)(L,\|\cdot\|e^{-\varphi}) by Chambert-Loir is the limit of the measures μm:=(θ+d​dc​φm)n\mu_{m}:=(\theta+dd^{c}\varphi_{m})^{n}, see [CL06, Proposition 2.7]. But after replacing φm\varphi_{m} by φm+εm\varphi_{m}+\varepsilon_{m} with a suitable sequence εm↘0\varepsilon_{m}\searrow 0, we may assume that the sequence φm\varphi_{m} is decreasing, hence μ=(θ+d​dc​φ)n\mu=(\theta+dd^{c}\varphi)^{n} by Theorem 3.1.

Original mathematics by the credited authors. Source-backed reader collection; mathematical self-containment is not assessed.