Results 11 to 20 of about 738 (35)

Isometry Lie algebras of indefinite homogeneous spaces of finite volume

open access: yesProceedings of the London Mathematical Society, Volume 119, Issue 4, Page 1115-1148, October 2019., 2019
Abstract Let g be a real finite‐dimensional Lie algebra equipped with a symmetric bilinear form ⟨·,·⟩. We assume that ⟨·,·⟩ is nil‐invariant. This means that every nilpotent operator in the smallest algebraic Lie subalgebra of endomorphisms containing the adjoint representation of g is an infinitesimal isometry for ⟨·,·⟩.
Oliver Baues   +2 more
wiley   +1 more source

Chern‐Simons forms of pseudo‐Riemannian homogeneity on the oscillator group

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 47, Page 3007-3014, 2003., 2003
We consider forms of Chern‐Simons type associated to homogeneous pseudo‐Riemannian structures. The corresponding secondary classes are a measure of the lack of a homogeneous pseudo‐Riemannian space to be locally symmetric. In the present paper, we compute these forms for the oscillator group and the corresponding secondary classes of the compact ...
P. M. Gadea, J. A. Oubiña
wiley   +1 more source

Introduction to Grassmann manifolds and quantum computation

open access: yesJournal of Applied Mathematics, Volume 2, Issue 8, Page 371-405, 2002., 2002
Geometrical aspects of quantum computing are reviewed elementarily for nonexperts and/or graduate students who are interested in both geometry and quantum computation. We show how to treat Grassmann manifolds which are very important examples of manifolds in mathematics and physics.
Kazuyuki Fujii
wiley   +1 more source

Some relations between Hodge numbers and invariant complex structures on compact nilmanifolds

open access: yesComplex Manifolds, 2017
Let N be a simply connected real nilpotent Lie group, n its Lie algebra, and € a lattice in N. If a left-invariant complex structure on N is Γ-rational, then HƏ̄s,t(Γ/N) ≃ HƏ̄s,t(nC) for each s; t.
Yamada Takumi
doaj   +1 more source

A note on the uniqueness of the canonical connection of a naturally reductive space [PDF]

open access: yes, 2012
We extend the result in J. Reine Angew. Math. 664, 29-53, to the non-compact case. Namely, we prove that the canonical connection on a simply connected and irreducible naturally reductive space is unique, provided the space is not a sphere, a compact Lie
Olmos, Carlos, Reggiani, Silvio
core   +3 more sources

A condition for a perfect-fluid space-time to be a generalized Robertson-Walker space-time [PDF]

open access: yes, 2016
A perfect-fluid space-time of dimension n>3 with 1) irrotational velocity vector field, 2) null divergence of the Weyl tensor, is a generalised Robertson-Walker space-time with Einstein fiber. Condition 1) is verified whenever pressure and energy density
De, Uday Chand   +2 more
core   +2 more sources

Contact metric manifolds with large automorphism group and (κ, µ)-spaces

open access: yesComplex Manifolds, 2019
We discuss the classifiation of simply connected, complete (κ, µ)-spaces from the point of view of homogeneous spaces. In particular, we exhibit new models of (κ, µ)-spaces having Boeckx invariant -1.
Lotta Antonio
doaj   +1 more source

Contact manifolds, Lagrangian Grassmannians and PDEs

open access: yesComplex Manifolds, 2018
In this paper we review a geometric approach to PDEs. We mainly focus on scalar PDEs in n independent variables and one dependent variable of order one and two, by insisting on the underlying (2n + 1)-dimensional contact manifold and the so-called ...
Eshkobilov Olimjon   +3 more
doaj   +1 more source

Corrigendum for "A geometric proof of the Karpelevich-Mostow theorem" [PDF]

open access: yes, 2016
Corollary 2.3 in our paper "A geometric proof of the Karpelevich-Mostow theorem", Bull. Lond. Math. Soc. 41 (2009), no. 4, 634-638, is false. Here we give a counterexample and show how to avoid the use of this corollary to give a simpler proof of ...
Di Scala, Antonio J., Olmos, Carlos
core  

Examples of naturally reductive pseudo-Riemannian Lie groups

open access: yes, 2011
We provide examples of naturally reductive pseudo-Riemannian spaces, in particular an example of a naturally reductive pseudo-Riemannian 2-step nilpotent Lie group $(N, _N)$, such that $_N$ is invariant under a left action and for which the center is ...
Ovando, Gabriela P.
core   +1 more source

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