Algèbres de Sobolev Généralisées

We examine the structure of a generalized Sobolev spaces. We also exhibit a class of locally uniformlyA-convex algebras, the unitization of which are not the same type.

     

Algèbres pré-Lie et algèbres de Hopf liées à la renormalisation

We describe the rôle of the notion of pre-Lie algebra in the combinatorics of renormalization, as formalized by Connes and Kreimer, and in the study of flows of vector fields.     

Algèbres de Poisson et Algèbres de Lie Résolubles

Let 𝔤 be a solvable Lie algebra and Q an (ad 𝔤)-stable prime ideal of the symmetric algebra S(𝔤) of 𝔤. If E denotes the set of nonzero elements of S(𝔤)/Q which are eigenvectors for the adjoint action of 𝔤 on S(𝔤)/Q, then the localization (S(𝔤)/Q) _E has a natural structure of Poisson algebra. We study this algebra here.

Soient 𝔤 une algèbre de Lie résoluble et Q un idéal premier (ad 𝔤)-stable de l'algèbre symétrique S(𝔤) de 𝔤. Si E est l'ensemble des éléments non nuls de S(𝔤)/Q qui sont vecteurs propres pour l'action adjointe de 𝔤 dans S(𝔤)/Q, l'algèbre localisée (S(𝔤)/Q) _E a une structure naturelle d'algèbre de Poisson. On étudie ici cette algèbre.     

Déformations d'algèbres de Weyl

We study here the rigidity of algebras which are the completion of the Weyl algebra A or the universal enveloping algebra A′ of the Lie algebra of the 2k+1 dimensional Heisenberg group. We define a canonical completion A_* of A and of A and prove that A_* does not does not have any continuous, Sp(k)-invariant deformation. Finally, we study the cohomology group associated to the problem of deformation of A′ and its completion. The invariant cohomology is one dimensional.     

Moyennes uniformes et moyennes suivant une marche aléatoire

Summary Let be a bounded function on such that converges towards l as n goes to infinity, uniformly with respect to m. Let {X _n} be a random walk on , not concentrated on a proper subgroup of Then, with probability 1, converges towards l as n goes to infinity. The result also holds for any countable abelian group instead of . Other modes of convergence are considered (Cesaro convergence of order >1/2). The Cesaro convergence of expressions such that (X _n) (X _n+1) is also investigated.     

Invariance spectrale des algèbres d'opérateurs pseudodifférentiels

We construct and study several algebras of pseudodifferential operators that are closed under holomorphic functional calculus. This leads to a better understanding of the structure of inverses of elliptic pseudodifferential operators on certain non-compact manifolds. It also leads to decay properties for the solutions of these operators. To cite this article: R. Lauter et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 1095–1099.     

Dimension de Hochschild des algèbres graduées

It is a basic fact that the global dimension of a connected $\mathbb{N}$-graded algebra coincides with the projective dimension of the trivial module. This result is recovered by proving that the Hochschild dimension is equal to the projective dimension of the trivial module. Thus the result becomes more natural with bimodules entering into the picture. To cite this article: R. Berger, C. R. Acad. Sci. Paris, Ser. I 341 (2005).     

Représentations indécomposables des superalgèbres de Lie spéciales linéaires

The main result of this Note is a classification of finite dimensional representations of the Lie superalgebra sl(m, 1) of supertraceless endomorphisms of the supervector space ℂ^{m + s} (m ∈ ℕ^*. The analogous problem for sl (m, n) has wild type when m, n ≥ 2.     

Sur les identités polynomiales vérifiées par les algèbres de rétrocroisement

We study the ideal of polynomial identities of a single indeterminate satisfied by all backcrossing algebras. For this we distinguish two categories according to whether or not these algebras satisfy an identity for the plenary powers. For each category, we give the generators for the vector space of identities, a condition for any object belonging to one of these two categories verify a given identity, a necessary and su?cient condition that a polynomial is an identity and we study the existence of an idempotent element. We give a method which brings the search of identities satified by the backcrossing algebras to the solution of linear systems and we illustrate this method by constructing generators of homogeneous and non homogeneous identities of degrees less than 8.     

Algèbres localement uniformémentA-pseudo-convexes advertiblement complètes

We examine the structure and the spectral properties of locally uniformlyA-pseudo-convex algebras.      

Décomposition spectrale dans des algèbres munies d'un star-produit

Summary The purpose of this paper is to study, in intrinsic way, the Moyal's product, defined in the flat space R ²ⁿ. This product is defined here with the twisted convolution and the Fourier transform. The S(R ²ⁿ) and L²(R ²ⁿ) spaces are_*5-algebras. Because of this definition, the_*V-product of some tempered distributions is defined. Let O _M ^v be the set of multiplication operators in S(R ²ⁿ). By transposition, the S(R ²ⁿ) space is a right-module on O _M ^v . The support of f_*v g is different from the support of f·g; under large enough hypotheses, there is a Taylor's formula for the star-product function of the v variable. The ^v space of the multiplication operators in L²(R ²ⁿ) is defined here as the space of tempered distributions, the image of which is the set of bounded operators in L²(R ²ⁿ) by the Weyl map. After the study of ^v space, it is possible to show the spectral resolution of the real elements of ^v or of O _M ^v , which satisfies a, probably superfluous, hypothesis.     

Propriétés Analytiques du Spectre dans les Algèbres de Jordan-Banach

If f() is an analytic function from a domain D of the complex plane into a Jordan-Banach algebra we prove that Sp f() is an analytic multivalued function. From this derives the subharmonicity of Log (f()), where denotes the spectral radius. We apply these results to prove that a Jordan-Banach algebra A is associative if and only if the spectral radius is subadditive and submultiplicative on A and to prove that A/Rad A is isomorphic to the complex plane if and only if each element of A has only one point in its spectrum.

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Le travail du permier auteur a été subventionné par le Conseil de recherches en sciences naturelles et en génie du Canada (subvention A 7668)     

Erratum to: Algèbres de lie quasi-réductives

In Corollary 12(ii) and Theorem 13(v) of [1] we omitted the hypothesis dim $ \mathfrak{z}\leq 1 $ . Moreover, in some places the symbol $ \mathbb{K} $ must be replaced by the symbol $ {{\mathbb{K}}^{\times }} $ .     

Train Algèbres Alternatives: Relation Entre Nilindice et Degré

We determine train polynomials for power associative algebras and for alternative train algebras. We show bonds between polynomials and nilindices of some factors of the Peirce decomposition.     

Sur les algèbres formelles associées par déformation a une variété symplectique

Résumé Sur une varieté symplectique (W, F), on considère une algébre associative formelle (E(N;v),x_v) obtenue par déformation du produit usuel des fonctions et satisfaisant à des hypothèses générales concernant le crochet de Poisson. Cette algèbre est déterminée de manièr unique par l'algèbre de Lie qu'elle engendre. On détermine les dérivations et les automorphismes de l'algèbre associative.     

Sur les idéaux induits dans les algèbres enveloppantes

Résumé Soient une algèbre de Lie de dimension finie et une sousalgèbre de Lie de . Je montre que l'induction, qui envoie les idéaux de l'algèbre enveloppante de dans les idéaux de l'algèbre enveloppante de , commute, à une torsion près, à l'anti-automorphisme principal. La résolution libre standard de la représentation triviale d'une algèbre de Lie joue un rôle important dans la démonstration.

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Summary Let be a finite dimensional Lie algebra, and a Lie subalgebra. I show that the induction map, between the sets of ideals in the enveloping algebras of and , commutes, up to a twisting, with the principal anti-automorphism. The standard free resolution of the trivial representation of a Lie algebra plays an important role in the proof.

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Convention. On fixe un corps commutatifk. Tous les espaces vectoriels, produits tensoriels et algèbres considérés dans cet article sont surk.

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Notations. Si g est une algèbre de Lie, on noteU(g) son algèbre enveloppante. On noteu l'anti-automorphisme principal deU(g): c'est l'antiautomorphisme tel que pourXg. Si est une forme linéaire sur g, nulle sur [g,g], on noteuu l'automorphisme deU(g) tel queX =X+(X) pourXg. Si g est de dimension finie, la fonction module de g est la forme linéaireXtradX.     

Variété des lois d'algèbres de Lie nilpotentes

Let N _nbe the variety of n-dimensional complex Lie algebra laws. For n12, two irreducible components in the variety N _nare described. The characteristically nilpotent filiform Lie algebras are studied.