Propriétés analytiques du spèctre dans les algèbres de Jordan-Banach.
Nous généralisons un résultat de dualité dans les représentations coinduites établi par M. Duflo (dans [Du]) dans le cas des algèbres de Lie de dimension finie. La démonstration que nous en proposons utilise la superalgèbre des opérateurs différentiels sur le module coinduit ainsi que la correspondance, mise en évidence par J. Bernstein, entre -modules à droite et -modules à gauche. Elle n’est valable qu’en caractéristique zéro. Nous donnons aussi une interprétation de ce théorème en termes de...
Soient une variété algébrique complexe, lisse, irréductible, et deux espaces vectoriels complexes de dimension finie et un morphisme de dans l’espace Lin des applications linéaires de dans . Pour , on note et le noyau et l’image de , le morphisme de dans Lin qui associe à l’application linéaire . Soit i la dimension minimale de . On dit que ala propriété en si i est inférieur à i. Soient le dual de , S l’algèbre symétrique de , l’idéal de engendré par...
For any pair E,F of pseudotopological vector spaces, we endow the space L(E,F) of all continuous linear operators from E into F with a pseudotopology such that, if G is a pseudotopological space, then the mapping L(E,F) × L(F,G) ∋ (f,g) → gf ∈ L(E,G) is continuous. We use this pseudotopology to establish a result about differentiability of certain operator-valued functions related with strongly continuous one-parameter semigroups in Banach spaces, to characterize von Neumann algebras, and to establish...
We prove that a pure state on a -algebras or a JB algebra is a unique extension of some pure state on a singly generated subalgebra if and only if its left kernel has a countable approximative unit. In particular, any pure state on a separable JB algebra is uniquely determined by some singly generated subalgebra. By contrast, only normal pure states on JBW algebras are determined by singly generated subalgebras, which provides a new characterization of normal pure states. As an application we contribute...
It has been previously established that a Cremona transformation of bidegree (2,2) is linearly equivalent to the projectivization of the inverse map of a rank 3 Jordan algebra. We call this result the “-correspondence”. In this article, we apply it to the study of quadro-quadric Cremona transformations in low-dimensional projective spaces. In particular we describe new very simple families of such birational maps and obtain complete and explicit classifications in dimension 4 and 5.
This paper is devoted to new algebraic structures, called qualgebras and squandles. Topologically, they emerge as an algebraic counterpart of knotted 3-valent graphs, just like quandles can be seen as an "algebraization" of knots. Algebraically, they are modeled after groups with conjugation and multiplication/squaring operations. We discuss basic properties of these structures, and introduce and study the notions of qualgebra/squandle 2-cocycles and 2-coboundaries. Knotted 3-valent graph invariants...
In this article we use the expansion for biquantization described in [7] for the case of symmetric spaces. We introduce a function of two variables for any symmetric pairs. This function has an expansion in terms of Kontsevich’s diagrams. We recover most of the known results though in a more systematic way by using some elementary properties of this function. We prove that Cattaneo and Felder’s star product coincides with Rouvière’s for any symmetric pairs. We generalize some of Lichnerowicz’s...
We propose a definition of a quantised -differential algebra and show that the quantised exterior algebra (defined by Berenstein and Zwicknagl) and the quantised Clifford algebra (defined by the authors) of are natural examples of such algebras.