4,660 research outputs found
Successive minima of toric height functions
Given a toric metrized R-divisor on a toric variety over a global field, we
give a formula for the essential minimum of the associated height function.
Under suitable positivity conditions, we also give formulae for all the
successive minima. We apply these results to the study, in the toric setting,
of the relation between the successive minima and other arithmetic invariants
like the height and the arithmetic volume. We also apply our formulae to
compute the successive minima for several families of examples, including
weighted projective spaces, toric bundles and translates of subtori.Comment: To appear in Annales de l'Institut Fourier (Grenoble), 40 pages, 5
figure
Arithmetic geometry of toric varieties. Metrics, measures and heights
We show that the height of a toric variety with respect to a toric metrized
line bundle can be expressed as the integral over a polytope of a certain
adelic family of concave functions. To state and prove this result, we study
the Arakelov geometry of toric varieties. In particular, we consider models
over a discrete valuation ring, metrized line bundles, and their associated
measures and heights. We show that these notions can be translated in terms of
convex analysis, and are closely related to objects like polyhedral complexes,
concave functions, real Monge-Amp\`ere measures, and Legendre-Fenchel duality.
We also present a closed formula for the integral over a polytope of a function
of one variable composed with a linear form. This allows us to compute the
height of toric varieties with respect to some interesting metrics arising from
polytopes. We also compute the height of toric projective curves with respect
to the Fubini-Study metric, and of some toric bundles.Comment: Revised version, 230 pages, 3 figure
The Ciborium or Lantern Tower of Valencia Cathedral: Geometry, Construction and Stability
Early 18th century treatise writer Tomas Vicente Tosca1 includes in his Tratado de la montea y cortes de Canteria [On Masonry Design and Stone Cutting], what is an important documentary source about the lantern of Valencia Cathedral. Tosca writes about this lantern as an example of vaulting over cross arches without the need of buttresses. A geometrical description is followed by an explanation of the structural behavior which manifests his deep understanding of the mechanics of masonry structures. He tries to demonstrate the absence of buttresses supporting his thesis on the appropriate distribution of loads which will reduce the "empujos" [horizontal thrusts] to the point of not requiring more than the thickness of the walls to stand (Tosca [1727] 1992, 227-230). The present article2 assesses T osca' s appreciation studying how loads and the thrusts they generate are transmitted through the different masonry elements that constitute this ciborium. In order to do so, we first present a geometrical analysis and make considerations regarding its materials and construction methods to, subsequently, analyze its stability adopting an equilibrium approach within the theoretical framework of the lower bound limit analysis
Singularities of the biextension metric for families of abelian varieties
In this paper we study the singularities of the invariant metric of the
Poincar\'e bundle over a family of abelian varieties and their duals over a
base of arbitrary dimension. As an application of this study we prove the
effectiveness of the height jump divisors for families of pointed abelian
varieties. The effectiveness of the height jump divisor was conjectured by Hain
in the more general case of variations of polarized Hodge structures of weight
.Comment: 54 pages, accepted for publication in Forum Math. Sigm
Arithmetic positivity on toric varieties
We continue with our study of the arithmetic geometry of toric varieties. In
this text, we study the positivity properties of metrized R-divisors in the
toric setting. For a toric metrized R-divisor, we give formulae for its
arithmetic volume and its chi-arithmetic volume, and we characterize when it is
arithmetically ample, nef, big or pseudo-effective, in terms of combinatorial
data. As an application, we prove a Dirichlet's unit theorem on toric
varieties, we give a characterization for the existence of a Zariski
decomposition of a toric metrized R-divisor, and we prove a toric arithmetic
Fujita approximation theorem.Comment: 53 page
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