Affine Lie algebraic origin of constrained KP hierarchies

An affine sl(n + 1) algebraic construction of the basic constrained KP hierarchy is presented. This hierarchy is analyzed using two approaches, namely linear matrix eigenvalue problem on hermitian symmetric space and constrained KP Lax formulation and it is shown that these approaches are equivalent. The model is recognized to be the generalized non-linear Schrödinger (GNLS) hierarchy and it is used as a building block for a new class of constrained KP hierarchies. These constrained KP hierarchies are connected via similarity-Bäcklund transformations and interpolate between GNLS and multi-boson KP-Toda hierarchies. Our construction uncovers the origin of the Toda lattice structure behind the latter hierarchy. © 1995 American Institute of Physics.

Closed expressions for Lie algebra invariants and finite transformations

A simple procedure to obtain complete, closed expressions for Lie algebra invariants is presented. The invariants are ultimately polynomials in the group parameters. The construction of finite group elements requires the use of projectors, whose coefficients are invariant polynomials. The detailed general forms of these projectors are given. Closed expressions for finite Lorentz transformations, both homogeneous and inhomogeneous, as well as for Galilei transformations, are found as examples.

La transformation productive 20 ans aprés: problémes anciens, nouvelles opportunités. Synthése

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Rapport du Groupe de Travail Spécial Créé aux Termes de la Résolution 553(XXVI)

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Resolución 3: Establecimiento de un Grupo Mixto de Trabajo con la Organización de Alimentación y Agricultura = Resolution 3: Establishment of a Joint Working Party with the Food and Agriculture Organization = Résolution 3: Création d'un groupe mixte de travail avec l'Organisation pour l'Alimentation et l'Agriculture

El símbolo E/840/Rev.1 corresponde a la edición bilingüe inglés/francés publicada en 1953

Informe de la Reunión del Grupo Especial de Trabajo Establecido en Virtud de la Resolución 553(XXVI) = Report of the Meeting of the Ad Hoc Working Group Established Pursuant to Resolution 553(XXVI) = Rapport de la Réunion du Groupe de Travail Spécial Créé aux Termes de la Résolution 553(XXVI)

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Reunión de Representantes de Países Miembros de la CEPAL ante las Naciones Unidas para Conocer el Informe de la Reunión del Grupo Especial de Trabajo = Meeting of Representatives of States Members of ECLAC to the United Nations to Hear the Report of the Meeting of the ad hoc Working Group = Réunion des Représentants des Pays Membres de la CEPALC auprès Nations Unies Visant à Prendre Connaissance du Rapport de la Réunion du Groupe de Travail Spécial

Rev.1 sólo en español