Equirépartition des coefficients de Fourier des fonctions L de carrés et de cubes symétriques

Dans ce travail, on étudie l’équirépartition et l’équirépartition harmonique des coefficients de Fourier des fonctions L de carrés et de cubes symétriques d’une forme primitive.     

Différentiation des capacités et des intégrales de Choquet

For any subadditive capacity κ on R dominated by a Radon measure, we show that lim κ (χ − δ, χ + ε]/(δ + ε) = d_κ (χ) exists for a.a. χ, as δ + ε → 0. Moreover, the Choquet integrals of any positive mesurable g satisfy

     

Réalisation de Hodge des motifs de Voevodsky

Sur un sous-corps du corps des complexes, nous associons à un objet de la catégorie des motifs géométriques de Voevodsky un Z-complexe de Hodge mixte de Deligne (Inst Hautes études Sci Publ Math 44:5–77, [D74]). Les filtrations par le poids et de Hodge sont représentées par des foncteurs de troncature, d’un complexe des poids à la Bondarko (J K-Theory 6(3):387–504, [Bo10a]) pour la première et troncature du complexe de De Rham (Lecomte Wach, Manuscr Math 129:75–90, [LW09]) pour l’autre.     

Géométrie des espaces de Banach ayant des approximations de l'identité contractantes

Let a, c ≥ 0 and let B be a compact set of scalars. We introduce property M^* (a, B, c) of Banach spaces X which is a geometric property of Banach spaces generalizing property (M^*) due to Kalton. Using M^*(a, B, c) with max ¦B¦ + c > 1, we characterize intrinsically a large class of shrinking approximations of the identity, including those related to M-, u-, and h-ideals of compact operators. We also show that the existence of these approximations of the identity is separably determined. As an application, we study ideals of compact and approximable operators. In particular, this provides an alternative unified and easier approach to the theories of M-, u-, and h-ideals of compact operators.     

Geométrie des suites de Kronecker

Let Θ be a element of the d-dimensional torus $\mathbb{T}$ ^d andτ the translationτ(x)=x + Θ. When d=1 there existe some partitions of $\mathbb{T}$ ¹ which are associated withτ. We prove the existence of partitions of $\mathbb{T}$ ^d which enjoyed the same kind of properties and whose elements (A _i ) _i≤n are convex polytopes. We also give a lower bound for the isotropic discrepancy of the sequence (nΘ) _nε?.     

Spectre des réseaux de poutres

We consider the spectral analysis of a model of networks of Euler-Bernoulli beams. We first give the characteristic equation for the spectrum. Secondly, in some particular situations, we show that the spectrum depends only on the structure of the graph. Thirdly, we investigate the asymptotic behaviour of the eigenvalues by proving the so-called Weyl's formula.     

Dégénérescence de sous-groupes discrets des groupes de Lie semi-simples

We prove that a sequence of faithful and discrete (but not necessarily with finite covolume) representations of a finitely generated group Γ in a semisimple Lie group, that goes to infinity, converges to an isometric action of Γ on an affine building, with controlled germ of apartment stabilizers.     

Fibre spéciale des hypersurfaces de petit degré

Building upon a result of J. Kollár on special fibres of families of hypersurfaces whose generic fibre satisfies the $C_1$-hypothesis, we establish a property of special fibres of families of hypersurfaces whose generic fibre satisfies the $C_2$-hypothesis. To cite this article: J.-L. Colliot-Thélène, C. R. Acad. Sci. Paris, Ser. I 346 (2008).     

Solutions de type multi-soliton des équations de KdV généralisées

We consider the generalized Korteweg–de Vries equations in the subcritical and critical cases. Let R_j(t,x)=Q_cj(x?c_jt?x_j) be N soliton solutions of this equation, with corresponding speeds 0<c₁<c₂<?<c_N. In this Note, we give a sketch of the proof of the following result. Given $\text{{c}{}_{\mathrm{j}}\text{},}\text{{x}{}_{\mathrm{j}}\text{}}$, there exists one and only one solution ? of the generalized KdV equation such that 6?(t)?∑R_j(t)6_H¹→0 as t→+∞. Complete proofs will appear later. To cite this article: Y. Martel, C. R. Acad. Sci. Paris, Ser. I 338 (2004).     

Quelques remarques sur les actions analytiques des réseaux des groupes de Lie de rang supérieur

All the actions considered here are (real) analytic. Let г be a subgroup of finite index of SL(n,). We prove, in particular, the (global) homotopical rigidity, for both its standard affine action on the torus T^a (n ≥ 3), and its standard projective action on the sphere Sⁿ⁻¹ (n, ≥ 4).     

Quelques propriétés des solutions de l'équation de Ginzburg-Landau sur un ouvert de ∝2

For a solution u of –u=u(1–|u|²) on the whole plane, |u|<1 holds everywhere unless u=eⁱ for some ; the derivatives of order k have moduli a constant M _kdepending only on k. For a solution u on an open set ², the moduli of u and its derivatives have upper bounds depending only on the distance to ²\ therefore the set of solutions on a given is compact in C() for the topology of uniform convergence on compact subsets of . For a solution u such that |u|<1, 1–|u| satisfies an estimation similar to the classical Harnack inequality for positive harmonic functions.Finally, if is bounded and |u| has a lim supm at each boundary point, the |u|m in if m1, but if m<1 then |u| admits only a majorant S _m with values in ]m, 1[ and sufficient conditions are given for lim S _m =0 or S _m =O(m) as m0.