Zobrazeno 1 - 10
of 111
pro vyhledávání: '"Alekseevsky, Dmitri V."'
We prove that if a simply connected non-conformally flat conformal Lorentzian manifold $(M,c)$ admits an essential transitive group of conformal transformations, then there exists a metric $g\in c$ such that $(M,g)$ is a complete homogeneous plane wa
Externí odkaz:
http://arxiv.org/abs/2407.03095
We explicitly derive the Christoffel symbols in terms of adapted frame fields for the Levi-Civita connection of a Lorentzian $n$-manifold $(M, g)$, equipped with a prescribed optical geometry of K\"ahler-Sasaki type. The formulas found in this paper
Externí odkaz:
http://arxiv.org/abs/2310.10938
By Vinberg theory any homogeneous convex cone $\mathcal V$ may be realized as the cone of positive Hermitian matrices in a $T$-algebra of generalised matrices. The level hypersurfaces $\mathcal V_{q} \subset \mathcal V$ of homogeneous cubic polynomia
Externí odkaz:
http://arxiv.org/abs/2301.01168
Autor:
Alekseevsky, Dmitri V., Spiro, Andrea
The initial sections of the paper give a concise presentation, specially designed for a mathematically oriented audience, of some of the most basic facts on the functional architecture of early vision. Such information is usually scattered in a varie
Externí odkaz:
http://arxiv.org/abs/2202.10157
Publikováno v:
JHEP 11 (2021) 100
We consider the static, spherically symmetric and asymptotically flat BPS extremal black holes in ungauged N = 2 D = 4 supergravity theories, in which the scalar manifold of the vector multiplets is homogeneous. By a result of Shmakova on the BPS att
Externí odkaz:
http://arxiv.org/abs/2107.06797
We study Lorentzian manifolds $(M, g)$ of dimension $n\geq 4$, equipped with a maximally twisting shearfree null vector field $p_o$, for which the leaf space $S = M/\{\exp t p_o\}$ is a smooth manifold. If $n = 2k$, the quotient $S = M/\{\exp t p_o\}
Externí odkaz:
http://arxiv.org/abs/2009.07179
Let $M = G/H$ be an $(n+1)$-dimensional homogeneous manifold and $J^k(n,M)=:J^k$ be the manifold of $k$-jets of hypersurfaces of $M$. The Lie group $G$ acts naturally on each $J^k$. A $G$-invariant PDE of order $k$ for hypersurfaces of $M$ (i.e., wit
Externí odkaz:
http://arxiv.org/abs/2004.04021
Autor:
Alekseevsky, Dmitri V.
There are many equivalent definitions of Riemannian geodesics. They are naturally generalised to sub-Riemannian manifold, but become non-equivalent. We give a review of different definitions of geodesics of a sub-Riemannian manifold and interrelation
Externí odkaz:
http://arxiv.org/abs/1909.08275
In [Alekseevsky, Gutt, Manno, Moreno: "A general method to construct invariant PDEs on homogeneous manifolds", Communications in Contemporary Mathematics (2021)] the authors have developed a method for constructing $G$-invariant PDEs imposed on hyper
Externí odkaz:
http://arxiv.org/abs/1907.06283
Autor:
Alekseevsky, Dmitri V., Podestà, Fabio
Given a non compact semisimple Lie group $G$ we describe all homogeneous spaces $G/L$ carrying an invariant almost K\"ahler structure $(\omega,J)$. When $L$ is abelian and $G$ is of classical type, we classify all such spaces which are Chern-Einstein
Externí odkaz:
http://arxiv.org/abs/1811.04068