Quasi-regularity in semigroups
Left distributive quasitrivial groupoids are completely described and those of them which are subdirectly irreducible are found. There are also determined all left distributive algebras such that is a quasitrivial groupoid.
Soient un corps global, un -tore, un ensemble fini de places de . On note le complété de en . Soit , resp. , le groupe des points -rationnels, resp. -rationnels, de . Notons le sous-groupe compact maximal. Nous montrons que pour et convenables l’application induite par l’application diagonale n’est pas surjective. Cela implique que pour convenable le groupe ne couvre pas forcément toutes les classes de -équivalence de . Lorsque est un corps de fonctions d’une variable...
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...