Quelques remarques sur le cas sauvage.
We study bialgebra structures on quiver coalgebras and monoidal structures on the categories of locally nilpotent and locally finite quiver representations. It is shown that the path coalgebra of an arbitrary quiver admits natural bialgebra structures. This endows the category of locally nilpotent and locally finite representations of an arbitrary quiver with natural monoidal structures from bialgebras. We also obtain theorems of Gabriel type for pointed bialgebras and hereditary finite pointed...
Given a tuple of irreducible characters of we define a star-shaped quiver together with a dimension vector . Assume that is generic. Our first result is a formula which expresses the multiplicity of the trivial character in the tensor product as the trace of the action of some Weyl group on the intersection cohomology of some (non-affine) quiver varieties associated to . The existence of such a quiver variety is subject to some condition. Assuming that this condition is satisfied, we...
L’étude d’une algèbre symétrique à gauche (de dimension finie sur ) est liée à celle d’un groupe de transformations affines opérant avec trajectoire ouverte et groupe d’isotropie discret sur cette trajectoire. Son radical est défini grâce aux translations conservant cette trajectoire; l’algèbre est nilpotente si ce groupe opère de façon simplement transitive (les multiplications à droite sont alors nilpotentes). Le radical est le plus grand idéal à gauche nilpotent.