Measures (admissible metrics) [01J1]
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Measures (admissible metrics)
Let us now return to semi-positive metrized line bundles , approximated by smooth semi-positive metrized line bundles . I claim that for any -dimensional variety , the sequence of measures converges to a measure on .
To prove the claim, we may assume that have sections without common zeroes on . Let also consider a smooth function on ; let be the trivial line bundle with the section , metrized in such a way that . Then, one has
writing has the quotient of two ample metrized line bundles, we deduce from the existence of the local height pairing for admissible metrics that these integrals converge when . Consequently, the sequence of measures converges to a positive linear form on the space of smooth functions. By a theorem of Gubler ([34], Theorem 7.12), which builds on the Stone-Weierstraß theorem and the compactness of the Berkovich space , the space of smooth functions is dense in the space of continuous complex functions on . A positivity argument, analogous to the proof that positive distributions are measures, then implies that our linear form is actually a positive measure which deserves the notation
We then extend this definition by linearity to the case of arbitrary admissible line bundles. The total mass of this measure is again the multidegree of with respect to the line bundles (for ).