共查询到20条相似文献,搜索用时 31 毫秒
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《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》2001,332(4):365-368
This Note concerns the estimation of the parameter of the intensity of an inhomogeneous spatial Poisson process by the maximum likelihood method. We consider an intensity admitting a discontinuity along a closed curve depending of an unknown parameter. The established results show the consistency, the convergence in law and the convergence of the moments of the maximum likelihood estimator. 相似文献
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《Comptes Rendus Mathematique》2005,340(12):861-866
Here we characterize in a complete and explicit way the relations of algebraic dependence over of complex values of Hecke–Mahler series at algebraic points of the multiplicative group . Our result contains previous results of Loxton and van der Poorten, Mahler, and Masser. To cite this article: F. Pellarin, C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
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《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》1999,328(10):887-890
We consider a topological space which is locally isomorphic to the quotient of Rk by the action of a discrete group and we call it quasifold of dimension k. Quasifolds generalize manifolds and orbifolds and represent the natural framework for performing symplectic reduction with respect to the induced action of any Lie subgroup, compact or not, of a torus. We define quasitori, Hamiltonian actions of quasitori and the moment mapping for symplectic quasifolds, and we show that every simple convex polytope, rational or not, is the image of the moment mapping for the action of a quasitorus on a quasifold. 相似文献
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We study the intersection of a subvariety X of an abelian variety A over with the union of all the algebraic subgroups of A of given dimension d. Our main result states that if we remove a suitable exceptional subset from X and if d is small enough then the intersection enjoys a Northcott-like property: the points of bounded height on it form a finite
set. The condition on d involves only the dimension of X and the structure of A up to isogenies. We show how it can be weakened if we assume certain conjectures in the direction of an abelian version of
Lehmer's problem. The theorem is especially meaningful when X is a curve since it is then possible to bound the height and hence to prove finiteness of the set under consideration. This
generalises the result of E. Viada on powers of elliptic curves and is analogous to work of E. Bombieri, D. Masser and U.
Zannier on tori, whose general strategy we follow. 相似文献
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Emmanuel Rio 《Probability Theory and Related Fields》2001,119(2):163-175
We propose new concentration inequalities for maxima of set-indexed empirical processes. Our approach is based either on
entropy inequalities or on martingale methods. The improvements we get concern the rate function which is exactly the large
deviations rate function of a binomial law in most of the cases.
Received: 11 January 2000 / Revised version: 12 May 2000 / Published online: 14 December 2000 相似文献
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Nicolas Perrin 《manuscripta mathematica》2005,116(4):449-474
In the first part, we give some necessary conditions for a torsion free sheaf on a smooth threefold to be a reduced limit of vector bundles.In a second part of the article, we illustrate these results by reinterpreting a condition described by G. Ellingsrud and S.A. Strømme as a condition obtained in the first part. This enables us to identify, in a well known too big familly, the torsion free sheaves that are limit of vector bundles. 相似文献
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Résumé Dans une région des l'espace on considère l'écoulement d'un fluide et on fait l'hypothèse qu'il est pseudotridimensionnel, c'est-à-dire que son mouvement est stationnaire et qu'il existe un système de coordonnées curvilignes (y
1,y
2,y
3) tel que les surfaces coordonnéesy
3=constante sont des surfaces de courant. Cette hypothèse entraîne l'existence d'une fonction de courant (y
1,y
2,y
3). Si le fluide est parfait et barotrope on obtient que 3/ le long des lignes de courant oú 3 est la troisième composante contravariante du rotationnel de la vitesse et la densité de masse. Cette propriété permet de formuler une équation pour la fonction de courant, généralisant l'équation habituelle de la mécanique des fluides plans.
Let us consider a flow motion in a given special domain. We make the assumption that the movement of the fluid is pseudo-tridimensional, i.e., the flow motion is steady and there exists a system of curvilinear coordinates (y 1,y 2,y 3) such that stream surfaces are defined byy 3=constant. Under this assumption there exists a stream function .Whenever the fluid is perfect and barotropic, we show that 3/= constant on stream lines (where 3 is the 3rd contravariant component of the speed's curl and is the density).Using this property we are able to write an equation for the stream function, which embeds the usual equation for two-dimensional fluid movements.相似文献
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In this paper, we prove dispersive and Strichartz inequalities on the Heisenberg group. The proof involves the analysis of
Besov-type spaces on the Heisenberg group.
Le travail du troisième auteur est partiellement finacé par la NNSF de Chine. 相似文献
Le travail du troisième auteur est partiellement finacé par la NNSF de Chine. 相似文献
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Michel Méo 《Comptes Rendus Mathematique》2010,348(11-12):625-628
The obstructions, for a closed differential form on a projective manifold, to be cohomologous to an algebraic cycle with complex coefficients, are computed in terms of the Chow transformation. They can be expressed as an orthogonality condition, on the manifold itself, with families parametrized by the Grassmannian of currents which are completely determined. A parameter does not yield any obstruction if the associated projective subspace meets properly the manifold. The embedding of the manifold is degenerated, in view of applying the characterization of currents associated to algebraic cycles by the Chow transformation. We study the set of periods obtained when the parameter varies, in particular, we prove a continuity result, thanks to the constructibility of the Bernstein polynomial. When the cohomology class is rational, we conjecture that this set is connected. 相似文献
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Let P and Q be non-zero polynomials with integer coefficients; suppose that all the roots of Q are rational numbers, and that Q(n) 0 for every n N. Let q Z, with |q| 2, and let Q*. We prove that the number
is irrational.From this we deduce linear independence results over Q for the values at x = of Tschakaloff's function Ta(x) =
, of its derivatives, and of its primitives. The proof uses Loxton and Van der Poorten's extension of Mahler's transcendence method, which leads, in this case, only to irrationality results. 相似文献