Displaying similar documents to “Homology of invariants of a Weyl algebra under a finite group action. (Homologie des invariants d'une algèbre de Weyl sous l'action d'un groupe fini.)”

Sur les rétractes absolus Pn -valués de dimension finie

Robert Cauty (1998)

Fundamenta Mathematicae

Similarity:

We prove that a k-dimensional hereditarily indecomposable metrisable continuum is not a P k -valued absolute retract. We deduce from this that none of the classical characterizations of ANR (metric) extends to the class of stratifiable spaces.

Espace de twisteurs d’une variété presque hermitienne de dimension 6

Jean-Baptiste Butruille (2007)

Annales de l’institut Fourier

Similarity:

On s’intéresse à l’espace de twisteurs réduit d’une variété presque hermitienne, en relisant un article de N.R.O’Brian et J.H.Rawnsley (Ann. Global Anal. Geom., 1985). On traite la question laissée ouverte de la dimension 6. Cet espace est muni d’une structure presque complexe 𝒥 en utilisant la distribution horizontale de la connexion hermitienne canonique. On montre qu’une condition nécessaire d’intégrabilité de 𝒥 est que la variété soit de type  W 1 ⊕ W 4 dans la classification de Gray et Hervella....

Préimages d’espaces héréditairement de Baire

Ahmed Bouziad (1997)

Fundamenta Mathematicae

Similarity:

The main result is slightly more general than the following statement: Let f: X → Y be a quasi-perfect mapping, where X is a regular space and Y a Hausdorff totally non-meagre space; if X or Y is χ-scattered, or if Y is a Lasnev space, then X is totally non-meagre. In particular, the product of a compact space X and a Hausdorff regular totally non-meagre space Y which is χ-scattered or a Lasnev space, is totally non-meagre.

Compacts connexes invariants par une application univalente

Emmanuel Risler (1999)

Fundamenta Mathematicae

Similarity:

Let K be a compact connected subset of cc, not reduced to a point, and F a univalent map in a neighborhood of K such that F(K) = K. This work presents a study and a classification of the dynamics of F in a neighborhood of K. When ℂ K has one or two connected components, it is proved that there is a natural rotation number associated with the dynamics. If this rotation number is irrational, the situation is close to that of “degenerate Siegel disks” or “degenerate Herman rings” studied...