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The symmetry algebra and conserved Currents for Klein-Gordon equation on quantum Minkowski space

MaŁgorzata Klimek (1997)

Banach Center Publications

The symmetry operators for Klein-Gordon equation on quantum Minkowski space are derived and their algebra is studied. The explicit form of the Leibniz rules for derivatives and variables for the case Z=0 is given. It is applied then with symmetry operators to the construction of the conservation law and the explicit form of conserved currents for Klein-Gordon equation.

The systolic constant of orientable Bieberbach 3-manifolds

Chady El Mir, Jacques Lafontaine (2013)

Annales de la faculté des sciences de Toulouse Mathématiques

A compact manifold is called Bieberbach if it carries a flat Riemannian metric. Bieberbach manifolds are aspherical, therefore the supremum of their systolic ratio, over the set of Riemannian metrics, is finite by a fundamental result of M. Gromov. We study the optimal systolic ratio of compact 3 -dimensional orientable Bieberbach manifolds which are not tori, and prove that it cannot be realized by a flat metric. We also highlight a metric that we construct on one type of such manifolds ( C 2 ) which...

The Tanaka-Webster connection for almost 𝒮 -manifolds and Cartan geometry

Antonio Lotta, Anna Maria Pastore (2004)

Archivum Mathematicum

We prove that a CR-integrable almost 𝒮 -manifold admits a canonical linear connection, which is a natural generalization of the Tanaka–Webster connection of a pseudo-hermitian structure on a strongly pseudoconvex CR manifold of hypersurface type. Hence a CR-integrable almost 𝒮 -structure on a manifold is canonically interpreted as a reductive Cartan geometry, which is torsion free if and only if the almost 𝒮 -structure is normal. Contrary to the CR-codimension one case, we exhibit examples of non normal...

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