Continuity of volumes on arithmetic varieties
Continuity of volumes on arithmetic varieties
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DOI:
10.1090/s1056-3911-08-00500-6
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发表时间:
2006-12
影响因子:
1.8
通讯作者:
A. Moriwaki
中科院分区:
文献类型:
--
作者:
A. Moriwaki
We introduce the volume function for C∞-hermitian invertible sheaves on an arithmetic variety as an analogue of the geometric volume function. The main result of this paper is the continuity of the arithmetic volume function. As a consequence, we have the arithmetic Hilbert-Samuel formula for a nef C∞-hermitian invertible sheaf. We also give another applications, for example, a generalized Hodge index theorem, an arithmetic Bogomolov-Gieseker’s inequality, etc. INTRODUCTION Let X be a d-dimensional projective arithmetic variety and Pic(X) the group of isomorphism classes of C∞-hermitian invertible sheaves onX . For L ∈ Pic(X), the volume vol(L) of L is defined by vol(L) = lim sup m→∞ log#{s ∈ H(X,mL) | ∥s∥sup ≤ 1} md/d! . For example, if L is ample, then vol(L) = deg(ĉ(L)·d) (cf. Lemma 3.1). This is an arithmetic analogue of the volume function for invertible sheaves on a projective variety over a field. The geometric volume function plays a crucial role for the birational geometry via big invertible sheaves. In this sense, to introduce the arithmetic analogue of it is very significant. The first important property of the volume function is the characterization of a big C∞hermitian invertible sheaf by the positivity of its volume (cf. Theorem 4.5). The second one is the homogeneity of the volume function, namely, vol(nL) = nvol(L) for all nonnegative integers n (cf. Proposition 4.7). By this property, it can be extended to Pic(X)⊗ Q. From viewpoint of arithmetic analogue, the most important and fundamental question is the continuity of vol : Pic(X)⊗Q → R, that is, the validity of the formula: lim e1,...,en∈Q e1→0,...,en→0 vol(L+ e1A1 + · · ·+ enAn) = vol(L) for any L,A1, . . . , An ∈ Pic(X) ⊗ Q. The main purpose of this paper is to give an affirmative answer for the above question (cf. Theorem 5.4). As a consequence, we have the following arithmetic Hilbert-Samuel formula for a nef C∞-hermitian invertible sheaf: Date: 5/January/2007, 17:30(JP), (Version 2.0). 1991Mathematics Subject Classification. 14G40, 11G50. 1