Displaying similar documents to “Non-Hamiltonian actions and Lie-algebra cohomology of vector fields.”

On the cohomology of vector fields on parallelizable manifolds

Yuly Billig, Karl-Hermann Neeb (2008)

Annales de l’institut Fourier

Similarity:

In the present paper we determine for each parallelizable smooth compact manifold M the second cohomology spaces of the Lie algebra 𝒱 M of smooth vector fields on M with values in the module Ω ¯ M p = Ω M p / d Ω M p - 1 . The case of p = 1 is of particular interest since the gauge algebra of functions on M with values in a finite-dimensional simple Lie algebra has the universal central extension with center Ω ¯ M 1 , generalizing affine Kac-Moody algebras. The second cohomology H 2 ( 𝒱 M , Ω ¯ M 1 ) classifies twists of the semidirect product...

Geometry of third order ODE systems

Alexandr Medvedev (2010)

Archivum Mathematicum

Similarity:

We compute cohomology spaces of Lie algebras that describe differential invariants of third order ordinary differential equations. We prove that the algebra of all differential invariants is generated by 2 tensorial invariants of order 2, one invariant of order 3 and one invariant of order 4. The main computational tool is a Serre-Hochschild spectral sequence and the representation theory of semisimple Lie algebras. We compute differential invariants up to degree 2 as application. ...

Second cohomology classes of the group of C 1 -flat diffeomorphisms

Tomohiko Ishida (2012)

Annales de l’institut Fourier

Similarity:

We study the cohomology of the group consisting of all C -diffeomorphisms of the line, which are C 1 -flat to the identity at the origin. We construct non-trivial two second real cohomology classes and uncountably many second integral homology classes of this group.

On compact symplectic and Kählerian solvmanifolds which are not completely solvable

Aleksy Tralle (1997)

Colloquium Mathematicae

Similarity:

We are interested in the problem of describing compact solvmanifolds admitting symplectic and Kählerian structures. This was first considered in [3, 4] and [7]. These papers used the Hattori theorem concerning the cohomology of solvmanifolds hence the results obtained covered only the completely solvable case}. Our results do not use the assumption of complete solvability. We apply our methods to construct a new example of a compact symplectic non-Kählerian solvmanifold.

L p , q -cohomology of warped cylinders

Yaroslav Kopylov (2009)

Annales mathématiques Blaise Pascal

Similarity:

We extend some results by Gol dshtein, Kuz minov, and Shvedov about the L p -cohomology of warped cylinders to L p , q -cohomology for p q . As an application, we establish some sufficient conditions for the nontriviality of the L p , q -torsion of a surface of revolution.