Propriétés de l'EMV de rupture de processus de Poisson

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.     

Constructibilité de de Rham p-adique

We use the theory of special modules to define the category of de Rham p-adic complexes on a smooth scheme over a perfect field and we prove a constructibility criterion implying the first finiteness properties.     

Modelo de un proceso de cristalización continua de un sorbete por medio de la metodología de momentos

Freezing is an important step in the manufacturing process of ice-cream and sorbet, since the operating conditions have a strong influence on the micro-structure, and consequently on the sensorial attributes of the final product. This steep of freezing is carried out by a scraped surface heat exchanger (SSHE) where the product quality is conditioned by process conditions as the evaporation temperature of a refrigerant fluid, the mix flow rate, the dasher speed and the cylinder pressure due to the air introduction. In order to study the relevance of a control system based on the influence of process variables on product quality, this paper presents a model for a continuous crystallization of a sorbet using the method of moments, which is validated by experimental data.The model created by this methodology has been able to represent the influence of the process conditions during the crystallization of the sorbet on the final product characteristics such as crystal size and the draw temperature in the outlet of the SSHE in absence of air. The model based in moments is studied as a reduced model of the population balance equation and includes the phenomena of heterogeneous nucleation and growth. This model developed represents minimal computational requirements and is highly adapted for optimization and/or process control tasks.     

Une variante de la méthode de majoration de Cauchy

Sans résumé Conférence faite au Congrès des mathématiciens scandinaves à Copenhague en ao?t 1964. 10-652932     

Estudio comparativo de distintos modelos de condiciones de contorno de impedancia en problemas acústicos

In this paper, different implementations of numerical locally reacting boundary conditions are studied for acoustic problems. In this comparative study we analyze two types of equations, the Euler equations and the wave equation. We also analyze both finite-differences time-domain (FDTD) algorithms, and pseudo-spectral time domain (PSTD) numerical schemes. We compare different numerical implementations existing in the literature by means of exhaustive numerical experiments. These numerical experiments allow for the study of the absorbing properties of the different schemes as a function of the frequency and the angle of the incident sound waves. This novel comparative study will help the acoustic engineer in order to choose the proper numerical scheme for his/her simulations.     

Uniformisation de l’espace des feuilles de certains feuilletages de codimension un

This paper deals with codimension one (may be singular) foliations on compact Kälher manifoldswhose conormal bundle is assumed to be pseudo-effective. Using currents with minimal singularities, we show that one can endow the space of leaves with a metric of constant non positive curvature wich may degenerate on a “rigidly” embedded invariant hypersurface.     

Sur l'anneau de cohomologie du schéma de Hilbert de C2

We express the product of the cohomology ring of the Hilbert scheme in terms of the center of the algebra of the symmetric group. We give a conjecture for the case of crepant resolutions of symplectic quotient singularities.     

Résolution de certains modules instables et fonction de partition de Minc

One constructs minimal injective resolutions for certain unstable modules that appear to be the mod 2 cohomology of Thom spectra. The terms of the resolution are tensor products of Brown–Gitler modules and Steinberg modules introduced by S. Mitchell and S. Priddy. A combinatorial result of Andrews shows that the alternating sum of the Poincaré series of the considered modules is zero. One gives homotopical applications of this result. To cite this article: D.H.H. Nguyen et al., C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Algébre de lie de type witt

Let ρ be an abelian group and k a commutative field. Inspired by the example of the Witt algebra, we introduce a family of ρ-graded Lie algebras (called Witt type Lie algebras) V = ⊕α?r Vα. where the dimension of each homogeneous component is 1. We characterise those which are simple and we give a complete classification of these Lie algebras. When P is free and the characteristic of k is zero, we show that the universal central extension of simple Witt type Lie algebras is 1-dimensional, and the corresponding cocycle is similar to the cocycle of the Virasoro algebra.     

Construction de polynômes de Kazhdan-Lusztig arbitraires

To each polynomial P with integral non-negative coefficients and constant term equal to 1, of degree d, we associate a pair of elements (y,w) in the symmetric group S_n, where n = 1 + d + P(l), for which we prove that the Kazhdan-Lusztig polynomial P_y,w equals P. This pair satisfies ℓ(w) - ℓ(y) = 2d + P(1) - 1, where ℓ(w) denotes the number of inversions of w.     

Sur le test de maximum de vraisemblance pour le mélange de populations

In [2] a theory is developed which under some regularity conditions, gives the asymptotical distribution of the likelihood ratio for testing the number of populations in a mixture. We give here two results. First, we exhibit a simple example where the likelihood ratio converges to +∞ with probability ½. Up to our knowledge, it is the first non-trivial example of a non-convergent likelihood test in a compact parameter space. Also, we give some enough regularity conditions allowing to apply the results of [2].     

Existence locale de solutions c∞ pour des equations de monge-ampere changeant de type

We prove the C∞ local solvability of the n-dimensional Monge-A mpé:ere equation det (u_ij + a_ij(x,u,▽u))= K(x) f(x, u, ▽u), f> 0, in a neighborhood of any point x₀ where K(x₀)= 0 but dK(x_o) ¦0.     

Etude de la Loi Locale de ω(n) Dans de Petits Intervalles

Let (n) be the number of prime factors counted without multiplicity of n. We give a uniform majoration for 1 which is valid for 2 y x.