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168,742 papers · 148 categories

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58116174232 · Jun 202619922001200920172026
48 results for Wallach flag manifold

This paper describes metrics with varying curvature properties in a specific manifold.

problem Characterizing regions in a manifold with specific curvature properties.
method Using a projected Ricci flow and studying the dynamics of regions in the manifold.
result Sign curvature maintenance and escaping in regions of the manifold.

We obtain a complete description of the moduli spaces of homogeneous metrics with strongly positive curvature on the Wallach flag manifolds W6W^6, W12W^{12} and W24W^{24}, which are respectively the manifolds of complete flags in C3\mathbb C^3, H3\mathbb H^3 and Ca3\mathbb{Ca}^3. Together with our earlier work, this concl…

2014-11-28abs ↗pdf ↗

In this paper, we use the technique of Finslerian submersion to deduce a flag curvature formula for homogeneous Finsler spaces. Based on this formula, we give a complete classification of even-dimensional smooth coset spaces G/HG/H admitting GG-invariant Finsler metrics with positive flag curvature. It turns out that t…

2014-07-14abs ↗pdf ↗

Study shows metrics on certain manifolds lose positive curvature under Ricci flow.

problem Understanding the dynamics of positively curved metrics on specific manifolds.
method Analysis of invariant metrics on SU(3)/T2\mathrm{SU}(3)/\mathrm{T}^2 and SU(m+2p)/S(U(m)imesU(p)imesU(p))\mathrm{SU}(m+2p)/\mathrm{S}(\mathrm{U}(m) imes\mathrm{U}(p) imes \mathrm{U}(p)) under homogeneous Ricci flow.
result Metrics lose positive intermediate Ricci curvature under Ricci flow for certain dimensions.

The paper explores symplectic connections on homogeneous spaces, finding a unique invariant connection.

problem Existence and uniqueness of symplectic connections on symplectic reductive homogeneous spaces.
method Introduced a family of invariant connections and showed the existence of a unique symplectic connection.
result Found a unique symplectic connection ablas abla^\mathbf{s} corresponding to a=b=frac13a=b= frac{1}{3}, which is Ricci-parallel.

Study harmonicity of normal almost contact structures on Riemannian manifolds.

problem Understanding harmonicity of normal almost contact structures.
method Analyzing harmonicity through associated sections of a twistor bundle and rewriting equations in terms of curvature tensor.
result Conditions relating harmonicity of almost contact metric and almost complex structures.

We give an overview of progress on homogeneous Einstein metrics on large classes of homogeneous manifolds, such as generalized flag manifolds and Stiefel manifolds. The main difference between these two classes of homogeneous spaces is that their isotropy representation does not contain/contain equivalent summands. We …

2016-05-19abs ↗pdf ↗

Formula for Lichnerowicz Laplacian on invariant metrics, deducing stability of Einstein manifolds.

problem Stability of Einstein manifolds in homogeneous spaces.
method Formula for Lichnerowicz Laplacian, computation of spectra, analysis of scalar curvature.
result Deduction of GG-stability and critical point types of Einstein metrics.

We study geodesics in generalized Wallach spaces which are expressed as orbits of products of three exponential terms. These are homogeneous spaces M=G/KM=G/K whose isotropy representation decomposes into a direct sum of three submodules m=m1m2m3\frak{m}=\frak{m}_1\oplus\frak{m}_2\oplus\frak{m}_3, satisfying the relations $[\fr…

2015-03-14abs ↗pdf ↗

We consider invariant Einstein metrics on the quaternionic Stiefel manifolds VpHnV_p\mathbb{H} ^n of all orthonormal pp-frames in Hn\mathbb{H}^n. This manifold is diffeomorphic to the homogeneous space Sp(n)/Sp(np)\mathrm{Sp}(n) / \mathrm{Sp}(n-p) and its isotropy representation contains equivalent summands. We obtain new Einstei…

2018-10-01abs ↗pdf ↗

Indecomposable symmetric Lorentzian manifolds of non-constant curvature are called Cahen-Wallach spaces. Their isometry classes are described by continuous families of real parameters. We derive necessary and sufficient conditions for the existence of compact quotients of Cahen-Wallach spaces in terms of these paramete…

2015-01-07abs ↗pdf ↗

Study on conformal transformations of Cahen-Wallach spaces, focusing on fixed points and discontinuous groups.

problem Characterizing conformal transformations of Cahen-Wallach spaces.
method Analyzing conformal transformations of indecomposable Lorentzian symmetric spaces, focusing on fixed points and discontinuous groups.
result Essential conformal transformations of conformally curved Cahen-Wallach spaces have fixed points, and such transformations cannot centralize essential homotheties.

The study characterizes and verifies equivariant embeddings of symmetric Kählerian manifolds.

problem Characterizing and verifying equivariant embeddings of symmetric Kählerian manifolds.
method Investigation motivated by Cartan and Wallach's theorem on symmetric spaces, focusing on CPn\mathbb{CP}^n and parallel plurimean curvature.
result If an equivariant embedding has parallel plurimean curvature, it is the extrinsically symmetric one.

We study geodesics of the form γ(t)=π(exp(tX)exp(tY))γ(t)=π(\exp(tX)\exp(tY)), $X,Y\in \fr{g}=\operatorname{Lie}(G)$, in homogeneous spaces G/KG/K, where π:GG/Kπ:G\rightarrow G/K is the natural projection. These curves naturally generalise homogeneous geodesics, that is orbits of one-parameter subgroups of GG (i.e. γ(t)=π(exp(tX))γ(t)=π(\exp (tX)), $X\in …

2016-11-14abs ↗pdf ↗

We introduce a geometric invariant that we call the index of symmetry, which measures how far is a Riemannian manifold from being a symmetric space. We compute, in a geometric way, the index of symmetry of compact naturally reductive spaces. In this case, the so-called leaf of symmetry turns out to be of the group type…

2013-02-13abs ↗pdf ↗

Study of a 3D system on Wallach spaces, finding interrelations with invariant metrics.

problem Understanding the dynamics of a 3D system on Wallach spaces.
method Analyzing the normalized Ricci flow on generalized Wallach spaces.
result Characterized interrelations between the normalized Ricci flow and invariant metrics on Wallach spaces.

We classify two-symmetric Lorentzian manifolds using methods of the theory of holonomy groups. These manifolds are exhausted by a special type of pp-waves and, like the symmetric Cahen-Wallach spaces, they have commutative holonomy.

2010-11-15abs ↗pdf ↗

For gauge groups U(1)U(1) and SO(3)SO(3) we classify invariant G2G_2-instantons for homogeneous coclosed G2G_2-structures on Aloff-Wallach spaces Xk,lX_{k,l}. As a consequence, we give examples where G2G_2-instantons can be used to distinguish between different strictly nearly parallel G2G_2-structures on the same Aloff-Walla…

2016-10-14abs ↗pdf ↗

The article constructs Spin(7) metrics with Aloff--Wallach spaces as orbits.

problem Creating Spin(7) metrics with specific geometric properties.
method Continuous 1-parameter families of non-compact Spin(7) metrics with chiralities, focusing on Aloff--Wallach spaces.
result Construction of Spin(7) metrics with Aloff--Wallach spaces as principal orbits, including geometric transitions.

Third-order symmetric Lorentzian manifolds, i.e. Lorentzian manifold with zero third derivative of the curvature tensor, are classified. These manifolds are exhausted by a special type of pp-waves, they generalize Cahen-Wallach spaces and second-order symmetric Lorentzian spaces.

2014-07-14abs ↗pdf ↗

Study finds bifurcation and local rigidity points for solutions to the Yamabe problem on Aloff-Wallach Spaces.

problem Yamabe problem on Aloff-Wallach Spaces
method Constructing 1-parameter families of solutions and examining changes in the Morse index as the parameter varies.
result Identifies bifurcation and local rigidity points for homogeneous solutions to the Yamabe problem.

Researchers compute the ν-invariant for specific G2-structures on Aloff-Wallach spaces.

problem Computing the ν-invariant for G2-structures on Aloff-Wallach spaces.
method Using Goette's formulas for η-invariants of homogeneous spaces, derived an explicit expression for ν.
result For the nearly-parallel G2-structures φ± on Nk,l, the ν-invariant is ν(φ±) = ±41.

Study finds conditions for Kähler-Einstein metrics on flag manifolds.

problem Characterizing Kähler-Einstein metrics on flag manifolds.
method Using Lie theoretic data, establish a sufficient and necessary condition for λ1λ_1-extremality.
result Identifies criteria for a metric to be a critical point of the first eigenvalue functional.

Study of weighted nonlinear flags in symplectic geometry.

problem Understanding the geometry of weighted nonlinear flags.
method Generalizing weighted nonlinear Grassmannians to Frechet manifolds and using them to describe coadjoint orbits.
result Description of coadjoint orbits of Hamiltonian diffeomorphisms using weighted isotropic nonlinear flags.

The paper studies Finsler manifolds with a new curvature concept.

problem Understanding Finsler manifolds with positive weighted flag curvature.
method Introducing a new curvature concept based on the flag curvature and a non-Riemannian quantity, T-curvature.
result Positive weighted flag curvature implies the manifold is diffeomorphic to Euclidean space.

Invariant Einstein metrics on generalized Wallach spaces have been classified except SO(k+l+m)/SO(k)×SO(l)×SO(m)SO(k+l+m)/SO(k)\times SO(l)\times SO(m). In this paper, we give a survey on the study of invariant Einstein metrics on generalized Wallach spaces, and prove that there are infinitely many spaces of the type $SO(k+l+m)/SO(k)\times SO(…

2015-11-09abs ↗pdf ↗

The paper classifies complex Dirac structures on flag manifolds.

problem Classifying invariant complex Dirac structures on flag manifolds.
method Described using roots of the Lie algebra and classified under BB-transformations.
result All invariant complex Dirac structures with constant real index on a maximal flag manifold are described.

Normalized Ricci flow preserves positivity of Ricci curvature on some generalized Wallach spaces.

problem Preserving positivity of Ricci curvature on generalized Wallach spaces.
method Normalized Ricci flow analysis on generalized Wallach spaces.
result Normalized Ricci flow does not preserve positivity of Ricci curvature on certain generalized Wallach spaces.

Classifies minimal immersions from S2S^2 into specific flag manifolds.

problem Classifying minimal immersions from S2S^2 into specific flag manifolds.
method Classification based on constant curvature and low-dimensional flag manifolds.
result Primitive minimal immersions of constant curvature from S2S^2 into F2,1,1F_{2,1,1} and F2,2,1F_{2,2,1} are classified.

Study spin chains and sigma models on flag manifolds, calculating spectra and geodesics.

problem Understanding the spectrum and geodesics of sigma models on flag manifolds.
method Connecting SU(n) spin chains to sigma models and calculating spectra and geodesics.
result Calculated the spectrum of the Laplace-Beltrami operator and geodesics for CP1\mathbb{CP}^1 and F3\mathcal{F}_3.