Results 11 to 20 of about 740 (36)

Ricci-flat and Einstein pseudoriemannian nilmanifolds

open access: yesComplex Manifolds, 2019
This is partly an expository paper, where the authors’ work on pseudoriemannian Einstein metrics on nilpotent Lie groups is reviewed. A new criterion is given for the existence of a diagonal Einstein metric on a nice nilpotent Lie group.
Conti Diego, Rossi Federico A.
doaj   +1 more source

Isospectral deformations of closed Riemannian manifolds with different scalar curvature [PDF]

open access: yes, 1997
We construct the first examples of continuous families of isospectral Riemannian metrics that are not locally isometric on closed manifolds, more precisely, on $S^n\times T^m$, where $T^m$ is a torus of dimension $m\ge 2$ and $S^n$ is a sphere of ...
Gordon, Carolyn S.   +4 more
core   +5 more sources

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 Primer on Carnot Groups: Homogenous Groups, Carnot-Carathéodory Spaces, and Regularity of Their Isometries

open access: yesAnalysis and Geometry in Metric Spaces, 2018
Carnot groups are distinguished spaces that are rich of structure: they are those Lie groups equipped with a path distance that is invariant by left-translations of the group and admit automorphisms that are dilations with respect to the distance.
Le Donne Enrico
doaj   +1 more source

Locally conformally Kähler solvmanifolds: a survey

open access: yesComplex Manifolds, 2019
A Hermitian structure on a manifold is called locally conformally Kähler (LCK) if it locally admits a conformal change which is Kähler. In this survey we review recent results of invariant LCK structures on solvmanifolds and present original results ...
Andrada A., Origlia M.
doaj   +1 more source

Review of the Coniopterygidae (Neuroptera) of North America With a Revision of the Genus Aleuropteryx

open access: yes, 1980
Psyche: A Journal of Entomology, Volume 87, Issue 3-4, Page 259-298, 1980.
Victor Johnson
wiley   +1 more source

A metric characterization of Carnot groups

open access: yes, 2014
We give a short axiomatic introduction to Carnot groups and their subRiemannian and subFinsler geometry. We explain how such spaces can be metrically described as exactly those proper geodesic spaces that admit dilations and are isometrically ...
Donne, Enrico Le
core   +1 more source

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

Observability on the classes of non-nilpotent solvable three-dimensional Lie groups

open access: yesOpen Mathematics
In control theory, researchers need to understand a system’s local and global behaviors in relation to its initial conditions. When discussing observability, the main focus is on the ability to analyze the system using an output space defined by an ...
Ayala Victor   +2 more
doaj   +1 more source

Metric lines in the jet space

open access: yesAnalysis and Geometry in Metric Spaces
In the realm of sub-Riemannian manifolds, a relevant question is: what are the metric lines (isometric embedding of the real line)? The space of kk-jets of a real function of one real variable xx, denoted by Jk(R,R){J}^{k}\left({\mathbb{R}},{\mathbb{R}}),
Bravo-Doddoli Alejandro
doaj   +1 more source

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