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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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Résumé Les auteurs donnent une formule d'intégration par parties dans le cadre des espaces topologiques ordonnés adopté par l'un
d'eux ([2]) pour sa théorie générale des fonctions de répartition. 相似文献
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Gaël Rémond 《Inventiones Mathematicae》2000,142(3):513-545
Faltings has proven the following conjecture of Lang: if A is an abelian variety over a number field and X any subvariety then all rational points of X lie on a finite number N of translates, contained in X, of abelian subvarieties of A. We provide an upper bound for N whose main feature is uniformity in X since it does not depend on the height of X. Moreover, the bound is completely explicit. Together with the result of a previous paper, the heart of the proof is a suitable
generalization of Mumford’s theorem for curves.
Oblatum 20-III-2000 & 3-V-2000?Published online: 16 August 2000 相似文献
Décompte dans une conjecture de Lang
Oblatum 20-III-2000 & 3-V-2000?Published online: 16 August 2000 相似文献
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Pierre Lelong 《Archiv der Mathematik》1958,9(2):161-166
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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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Trygve Nagell 《Arkiv f?r Matematik》1964,5(3-4):343-356
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We investigate some properties of the integral, with respect to a parametrized probability, of a multifunction whose values are compact (nonconvex) subsets of a Banach space. We obtain an approximation of the closure of the Aumann's integral of a multifunction with values in a separable Banach space by the Aumann's integral of multifunctions with values in finite dimensional spaces. 相似文献
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Waclaw Sierpinski 《Annali di Matematica Pura ed Applicata》1955,39(1):69-74
Résumé L'auteur donne des conditions nécessaires et suffisantes pour qu'un nombre naturel n soit un ? nombre pratique ?, c'est-à-dire
pour que tout nombre naturel <-n soit une somme de diviseurs naturels distincts du nombre n.
à Mauro Picone pour son 70me anniversaire. 相似文献
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Lucien Godeaux 《Annali di Matematica Pura ed Applicata》1961,53(1):9-19
Résumé On établit que si la suite deLaplace associée dans l'espace ? cinq dimensions à une surface de l'espace ordinaire est terminée, il existe deux congruences W dont
la surface est une nappe focale et qui sont liées intrinsèquement à cette surface.
à M. Enrico Bompiani pour son Jubilé scientifique. 相似文献
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Bernard Lapeyre 《Probability Theory and Related Fields》1990,87(2):189-207
Résumé Nous considérons l'équation différentielle stochastique réfléchie à valeur dansR
2 associée à l'opérateur différentiel dégénéré (1/2)2/x
2+x/y. On étudie alors le phénomène d'excursion autour du point origine. En particulier, on peut identifier la loi de l'inverse du temps local comme un subordinateur stable d'ordre 1/4 et en donner une formule du type temps d'occupation. Ceci permet alors d'étudier le comportement de la loi du processus au voisinage du point origine pour préciser, dans ce cas particulier, des résultats obtenus par Krée (1985) grâce à des méthodes analytiques.
Summary We consider theR 2-valued reflected stochastic differential equation associated with the degenerated differential operator (1/2)2/x 2+x/y. We study the excursion phenomenon around the point (0, 0). We are able to identify the law of the inverse of the local time as a stable subordinator with order 1/4 and to give for it an occupation time formula. These facts enable us to study the behavior of the law of the process near the point (0, 0) and to refine, in our case, results obtained by Krée (1985) by means of analytical methods.相似文献
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Ivan Nourdin 《Comptes Rendus Mathematique》2005,340(8):611-614
We study here classical approximation schemes (Euler, Milshtein) associated with a differential equation of the type , , where g is a function, supposed Hölderian of order α somewhere in . When is the trajectory of fractional Brownian movement, we deduce probability properties to refine the results. To cite this article: I. Nourdin, C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
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J. Czipszer 《Acta Mathematica Hungarica》1959,10(3-4):305-315
Sans résuméPrésenté parG. Alexits
Dédié à Monsieur le ProfesseurGeorges Alexits à l'occasion de son 60e anniversaire 相似文献
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《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》1999,328(6):459-462
In this paper we prove a generalization of the primality test in [3] for a wide class of iterated Ore extensions of a commutative polynomial ring. 相似文献
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It has long been conjectured that a closed convex surface of class C+2 whose principal curvatures K1, K2 satisfy the inequality (K1−c)(K2−c)≤0 with some constant c, must be a sphere. Partial results have been obtained by A.D. Aleksandrov, H.F. Münzner and D. Koutroufiotis.We reformulate the conjecture in terms of hedgehogs and we give a counter-example. Besides, we prove the conjecture for surfaces of constant width and give a new proof for analytic surfaces. 相似文献