929 research outputs found
Nilpotent bicone and characteristic submodule of a reductive Lie algebra
The nilpotent bicone of a finite dimensional complex reductive Lie algebra g
is the subset of elements in g x g whose subspace generated by the components
is contained in the nilpotent cone of g. The main result of this note is that
the nilpotent bicone is a complete intersection. This affirmatively answers a
conjecture of Kraft-Wallach concerning the nullcone. In addition, we introduce
and study the characteristic submodule of g. The properties of the nilpotent
bicone and the characteristic submodule are known to be very important for the
understanding of the commuting variety and its ideal of definition. In order to
study the nilpotent bicone, we introduce another subvariety, the principal
bicone. The nilpotent bicone, as well as the principal bicone, are linked to
jet schemes. We study their dimensions using arguments from motivic
integration. Namely, we follow methods developed in
http://arxiv.org/abs/math/0008002v5 .Comment: 48 pages. Remark 8 has been modified; one sentence was not correct.
We thank Kari Vilonen for pointing out this erro
The index of centralizers of elements of reductive Lie algebras
For a finite dimensional complex Lie algebra, its index is the minimal
dimension of stabilizers for the coadjoint action. A famous conjecture due to
Elashvili says that the index of the centralizer of an element of a reductive
Lie algebra is equal to the rank. That conjecture caught attention of several
Lie theorists for years. In this paper we give an almost general proof of that
conjecture.Comment: 27 pages in English. Lemmas 3.1 and 3.2 are removed. So Theorem 3.3
becomes Theorem 3.1 and its proof is simplifie
Évaluation préliminaire d’un projet de soins concertés en santé mentale jeunesse à Montréal : faire face à l’incertitude institutionnelle et culturelle
Cet article décrit un projet de soins concertés en santé mentale jeunesse dans un milieu pluriethnique de Montréal. Les auteurs examinent les ajustements à apporter au modèle prévalent pour répondre aux enjeux culturels et de coopération de services destinés à une population pluriethnique. Une évaluation qualitative préliminaire du projet révèle les nombreuses sources d’incertitude auxquelles sont confrontés les intervenants. Enfin, les auteurs formulent l’hypothèse selon laquelle les incertitudes, si elles génèrent malaise et confusion, permettent aussi une ouverture à l’innovation et à l’altérité.This article describes a collaborative mental health care project for youths, implemented in Montreal in a multiethnic setting. The authors examine the adjustments needed in the shared-care model to address the complexity of cultural and cooperation issues raised in the provision of services to a multiethnic population. A preliminary qualitative evaluation of the project shows how first-line workers face many uncertainties, stemming from both the institutional context and the multicultural reality of the population served. Results from this study advance the hypothesis that although uncertainties may generate discomfort and confusion, they may also open a space for innovation and acceptance of otherness.Este artÃculo describe un proyecto de cuidados multidisciplinarios en salud mental para la juventud en un medio pluriétnico de Montreal. Los autores examinan los ajustes a realizar al modelo prevaleciente para responder a los aspectos culturales de los servicios destinados a una población pluriétnica. Una evaluación cualitativa preliminar del proyecto revela las numerosas fuentes de incertidumbre a las que se enfrentan los interventores. Finalmente, los autores formulan la hipótesis según la cual la incertidumbre, si bien genera malestar y confusión, permite también la apertura a la innovación y a la alteridad.Este artigo descreve um projeto de atenções concertadas em saúde mental da criança e do adolescente em um meio multiétnico de Montreal. Os autores examinam os ajustes a fazer ao modelo prevalente para atender à s questões culturais dos serviços destinados a uma população multiétnica. Uma avaliação qualitativa preliminar do projeto revela as numerosas fontes de incerteza à s quais são confrontados os intervenientes. Finalmente, os autores formulam a hipótese segundo a qual as incertezas, se geram desconforto e confusão, permitem também uma abertura à inovação e à alteridade
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