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Homogeneous hessian manifolds

Hirohiko Shima (1980)

Annales de l'institut Fourier

A flat affine manifold is said to Hessian if it is endowed with a Riemannian metric whose local expression has the form g i j = ∂ 2 Φ ∂ x i ∂ x j where Φ is a C ∞ -function and { x 1 , ... , x n } is an affine local coordinate system. Let M be a Hessian manifold. We show that if M is homogeneous, the universal covering manifold of M is a convex domain in R n and admits a uniquely determined fibering, whose base space is a homogeneous convex domain not containing any full straight line, and whose fiber is an affine subspace of R n .

Homogeneous quaternionic Kähler structures on Alekseevskian 𝒲-spaces

Wafaa Batat, P. M. Gadea, Jaime Muñoz Masqué (2012)

Annales Polonici Mathematici

The homogeneous quaternionic Kähler structures on the Alekseevskian 𝒲-spaces with their natural quaternionic structures, each of these spaces described as a solvable Lie group, and the type of such structures in Fino's classification, are found.

Homogeneous Randers spaces admitting just two homogeneous geodesics

Zdeněk Dušek (2019)

Archivum Mathematicum

The existence of a homogeneous geodesic in homogeneous Finsler manifolds was investigated and positively answered in previous papers. It is conjectured that this result can be improved, namely that any homogeneous Finsler manifold admits at least two homogenous geodesics. Examples of homogeneous Randers manifolds admitting just two homogeneous geodesics are presented.

Homogeneous Riemannian manifolds with generic Ricci tensor

Włodzimierz Jelonek (2001)

Annales Polonici Mathematici

We describe homogeneous manifolds with generic Ricci tensor. We also prove that if 𝔤 is a 4-dimensional unimodular Lie algebra such that dim[𝔤,𝔤] ≤ 2 then every left-invariant metric on the Lie group G with Lie algebra 𝔤 admits two mutually opposite compatible left-invariant almost Kähler structures.

Homogeneous variational problems: a minicourse

David J. Saunders (2011)

Communications in Mathematics

A Finsler geometry may be understood as a homogeneous variational problem, where the Finsler function is the Lagrangian. The extremals in Finsler geometry are curves, but in more general variational problems we might consider extremal submanifolds of dimension m . In this minicourse we discuss these problems from a geometric point of view.

Homogeneous variational problems and Lagrangian sections

D.J. Saunders (2016)

Communications in Mathematics

We define a canonical line bundle over the slit tangent bundle of a manifold, and define a Lagrangian section to be a homogeneous section of this line bundle. When a regularity condition is satisfied the Lagrangian section gives rise to local Finsler functions. For each such section we demonstrate how to construct a canonically parametrized family of geodesics, such that the geodesics of the local Finsler functions are reparametrizations.

Homology and modular classes of Lie algebroids

Janusz Grabowski, Giuseppe Marmo, Peter W. Michor (2006)

Annales de l’institut Fourier

For a Lie algebroid, divergences chosen in a classical way lead to a uniquely defined homology theory. They define also, in a natural way, modular classes of certain Lie algebroid morphisms. This approach, applied for the anchor map, recovers the concept of modular class due to S. Evens, J.-H. Lu, and A. Weinstein.

Homotopie régulière inactive et engouffrement symplectique

François Laudenbach (1986)

Annales de l'institut Fourier

Une homotopie régulière ϕ t : Δ → ( M , ω ) , t ∈ [ 0 , 1 ] , dans une variété symplectique est dite inactive si en chaque point le déplacement infinitésimal est ω -orthogonal à l’espace tangent de l’objet déplacé. Si Δ est un polyèdre de M 2 n de dimension < n et si U est un ouvert de M , toute homotopie de Δ ↪ M jusqu’à Δ → U est déformable en une homotopie régulière inactive. On donne une application à l’engouffrement en géométrie symplectique.

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