Construction d'une cavité supraconductrice

Sans résumé     

Relèvement d'une mesure ergodique par un codage

Summary Let be a coding: BA, to which is associated a mapping from the set of ergodic measures on B to the set of ergodic measures on A . We derive a relation between the number of ergodic solutions of the equation where P is a given ergodic measure on A , and the ambiguousness of decoding for each of the solutions Q.

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Laboratoire de Probabilités, tour 46–56, 3 ème étage, 4, Place Jussieu, F-75230 Paris Cedex 05. Laboratoire associé au CNRS n°224 «Processus Stochastiques et Applications»     

Suite spectrale d'une extension d'algèbres de Leibniz

Leibniz homology is a non-commutative homology theory for Lie algebras which can be extended to a larger class of algebras: the Leibniz algebras. We construct a “Leibniz version” of the Hochschild-Serre spectral sequence.     

Solution viable d'une inclusion différentielle non convexe

We present a result on the existence of viable solutions for a class of multivalued differential equations with right-hand side not necessarily compact and convex.     

Décomposition locale d'une structure bihamiltonienne en produit Kronecker-symplectique

One shows that, around every point of a dense open set, a real analytic or holomorphic bihamiltonian structure decomposes into a Kronecker-symplectic product if a necessary condition on the characteristic polynomial of the symplectic factor holds.     

Algorithme d'encadrement de l'optimum global d'une fonction différentiable

The purpose of the method proposed is to estimate closely the minimum of a multivariate differentiable function and to localize all minimizers. The algorithm, using inclusion properties of interval arithmetic, gives an underestimation of the function; this process, then, may be integrated in a Branch and Bound algorithm, i.e., sub-box branching, elimination, and selection.     

Sur le polynôme principal d'une Algèbre

Sans résumé     

La C*-algèbre d'une quasi-représentation

We show that the C^* -algebra of the regular representation of a discrete group G onto a subset Σ of G is the reduced C^* -algebra of an r-discrete groupoid whose space of units is totally disconnected and contains Σ as a dense subset. The C^*-algebra of quasicrystals, some Cuntz-Krieger and crossed product algebras, and Wiener-Hopf algebras are particular cases of this construction     

L'anneau de cohomologie d'une variété de Seifert

All manifolds M considered in this Note are orientable Seifert 3-manifolds with base surface S² and infinite fundamental group π₁ (M). Our goal is to compute the cohomology ring H^* (M; Z/2Z). The ring structure will enable us to determine whether M admits a degree 1 map into RP³ or not. We describe the equivariant chain complex for the universal cover M of M, and give a diagonal approximation. The cohomology ring H^* (M; Z/2Z) is computed.     

Extension dans un cadre algébrique d'une formule de Weil

Let R be a commutative A-algebra, and f=(f ₁,…,f _n ) a quasi-regular sequence such that P=R/(f) is finitely generated and projective over A. In the algebraic residue formalism due to J. Lipman, we propose the analog of an analytic Weil's formula. As applications, we first give some criterions for homomorphism from A[z] to A[z] to be finite when A is a n\oe therian ring, and then an algebraic proof of the usual analytic Weil's formula. Received: 27 April 1998