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Invariant variational problems on principal bundles and conservation laws

Ján Brajerčík (2011)

Archivum Mathematicum

In this work, we consider variational problems defined by G -invariant Lagrangians on the r -jet prolongation of a principal bundle P , where G is the structure group of P . These problems can be also considered as defined on the associated bundle of the r -th order connections. The correspondence between the Euler-Lagrange equations for these variational problems and conservation laws is discussed.

Isospectral deformations of the Lagrangian Grassmannians

Jacques Gasqui, Hubert Goldschmidt (2007)

Annales de l’institut Fourier

We study the special Lagrangian Grassmannian S U ( n ) / S O ( n ) , with n 3 , and its reduced space, the reduced Lagrangian Grassmannian X . The latter is an irreducible symmetric space of rank n - 1 and is the quotient of the Grassmannian S U ( n ) / S O ( n ) under the action of a cyclic group of isometries of order n . The main result of this paper asserts that the symmetric space X possesses non-trivial infinitesimal isospectral deformations. Thus we obtain the first example of an irreducible symmetric space of arbitrary rank 2 , which is...

La trilogie du moment

Patrick Iglesias (1995)

Annales de l'institut Fourier

A toute deux-forme fermée, sur une variété connexe, on associe une famille d’extensions centrales du groupe de ses automorphismes par son tore des périodes. On discute ensuite quelques propriétés de cette construction.

Local structural stability of C 2 integrable 1-forms

Alcides Lins Neto (1977)

Annales de l'institut Fourier

In this work we consider a class of germs of singularities of integrable 1-forms in R n which are structurally stable in class C r ( r 2 if n = 3 , r 4 if n 4 ), whose 1-jet is zero at the singularity. In this class the stability depends essentially on the fact that the perturbations allowed are integrable.

Local symplectic algebra of quasi-homogeneous curves

Wojciech Domitrz (2009)

Fundamenta Mathematicae

We study the local symplectic algebra of parameterized curves introduced by V. I. Arnold. We use the method of algebraic restrictions to classify symplectic singularities of quasi-homogeneous curves. We prove that the space of algebraic restrictions of closed 2-forms to the germ of a 𝕂-analytic curve is a finite-dimensional vector space. We also show that the action of local diffeomorphisms preserving the quasi-homogeneous curve on this vector space is determined by the infinitesimal action of...

Modular vector fields and Batalin-Vilkovisky algebras

Yvette Kosmann-Schwarzbach (2000)

Banach Center Publications

We show that a modular class arises from the existence of two generating operators for a Batalin-Vilkovisky algebra. In particular, for every triangular Lie bialgebroid (A,P) such that its top exterior power is a trivial line bundle, there is a section of the vector bundle A whose d P -cohomology class is well-defined. We give simple proofs of its properties. The modular class of an orientable Poisson manifold is an example. We analyse the relationships between generating operators of the Gerstenhaber...

New estimates for elliptic equations and Hodge type systems

Jean Bourgain, Haïm Brezis (2007)

Journal of the European Mathematical Society

We establish new estimates for the Laplacian, the div-curl system, and more general Hodge systems in arbitrary dimension n , with data in L 1 . We also present related results concerning differential forms with coefficients in the limiting Sobolev space W 1 , n .

Non-decomposable Nambu brackets

Klaus Bering (2015)

Archivum Mathematicum

It is well-known that the Fundamental Identity (FI) implies that Nambu brackets are decomposable, i.e. given by a determinantal formula. We find a weaker alternative to the FI that allows for non-decomposable Nambu brackets, but still yields a Darboux-like Theorem via a Nambu-type generalization of Weinstein’s splitting principle for Poisson manifolds.

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