Zobrazeno 1 - 10
of 79
pro vyhledávání: '"Medori, Costantino"'
A complex flag manifold F= G /Q decomposes into finitely many real orbits under the action of a real form of G. Their embedding into F define on them CR manifold structures. We characterize the closed real orbits which are finitely nondegenerate.
Externí odkaz:
http://arxiv.org/abs/2211.16070
An {\em almost p-K\"ahler manifold} is a triple $(M,J,\Omega)$, where $(M,J)$ is an almost complex manifold of real dimension $2n$ and $\Omega$ is a closed real tranverse $(p,p)$-form on $(M,J)$, where $1\leq p\leq n$. When $J$ is integrable, almost
Externí odkaz:
http://arxiv.org/abs/2109.10939
We investigate the nondegeneracy of higher order Levi forms on weakly nondegenerate homogeneous $CR$ manifolds. Improving previous results, we prove that general orbits of real forms in complex flag manifolds have order less or equal $3$ and the comp
Externí odkaz:
http://arxiv.org/abs/2006.16576
We study finite dimensional almost and quasi-effective prolongations of nilpotent Z-graded Lie algebras, especially focusing on those having a decomposable reductive structural subalgebra. Our assumptions generalize effectiveness and algebraicity and
Externí odkaz:
http://arxiv.org/abs/1910.07896
In this paper we translate the necessary and sufficient conditions of Tanaka's theorem on the finiteness of effective prolongations of a fundamental graded Lie algebras into computationally effective criteria, involving the rank of some matrices that
Externí odkaz:
http://arxiv.org/abs/1806.09376
Autor:
Bozzetti, Cristina, Medori, Costantino
An almost complex manifolds $(M^4,J)$ of real dimension 4 with non-degenerate torsion bundle admit a double absolute parallelism and it is provided the classification of homogeneous $(M^4,J)$ having an associated non-solvable Lie algebra. We extend s
Externí odkaz:
http://arxiv.org/abs/1706.10068
We consider locally homogeneous $CR$ manifolds and show that, under a condition only depending on their underlying contact structure, their $CR$ automorphisms form a finite dimensional Lie group.
Comment: 22 pages
Comment: 22 pages
Externí odkaz:
http://arxiv.org/abs/1706.03512
Autor:
Medori, Costantino, Spiro, Andrea
We explicitly determine the structure equations of 5-dimensional Levi 2-nondegenerate CR hypersurfaces, using our recently constructed canonical Cartan connection for this class of CR manifolds. We also give an outline of the basic properties of abso
Externí odkaz:
http://arxiv.org/abs/1510.07264
T.-J. Li and W. Zhang defined an almost complex structure $J$ on a manifold $X$ to be {\em \Cpf}, if the second de Rham cohomology group can be decomposed as a direct sum of the subgroups whose elements are cohomology classes admitting $J$-invariant
Externí odkaz:
http://arxiv.org/abs/1211.2334
Autor:
Medori, Costantino, Spiro, Andrea
Let M be a CR manifold of hypersurface type, which is Levi degenerate but also satisfying a k-nondegeneracy condition at all points. This might be only if dim M is greater than or equal to 5 and if dim M = 5, then k= 2 at all points. We prove that fo
Externí odkaz:
http://arxiv.org/abs/1210.5638