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48 results for generalized structures

Defines a new Poisson structure for generalized Sasakian spaces.

problem No specific problem stated; focuses on new structure definition.
method Defines a canonical Poisson structure on generalized contact metric spaces.
result Shows distinction between generalized Sasakian and coKähler structures.

Study on types of generalized hypercomplex structures on tori and Kodaira-Thurston surface.

problem Characterizing types of generalized hypercomplex structures.
method Analysis of S2S^2-family of generalized complex structures and study of twistor spaces.
result Existence of generalized hypercomplex structures on 4n4n-dimensional tori with non-maximal types.

We study integrability of generalized almost contact structures, and find conditions under which the main associated maximal isotropic vector bundles form Lie bialgebroids. These conditions differentiate the concept of generalized contact structures from a counterpart of generalized complex structures on odd-dimensiona…

2009-12-29abs ↗pdf ↗

Characterizes integrability of generalized structures on Courant algebroids.

problem Integrability of generalized structures on Courant algebroids.
method Characterization via torsion-free generalized connections and Dirac generating operators.
result Criterion for integrability of generalized almost Hermitian structures and hyper-Hermitian structures.

No direct generalized complex structure can be induced from S6\mathbb S^6's nearly Kähler structure.

problem Existence of generalized complex structures on S6\mathbb S^6.
method Defined integrability in terms of the Dorfman bracket and studied S6\mathbb S^6's nearly Kähler structure.
result No generalized complex structure can be induced from S6\mathbb S^6's nearly Kähler structure.

Defines generalized Sasakian structures in contact geometry.

problem Understanding k-contact manifolds and CR manifolds.
method Introduced generalized Sasakian structures and proved their equivalence to Sasakian structures.
result k-contact manifolds are generalized Sasakian if and only if they are classically Sasakian.

We establish the conditions for the induced generalized metric F structure of an oriented hypersurface of a generalized Kähler manifold to be a generalized CRFK structure. Then, we discuss a notion of generalized almost contact structure on a manifold MM that is suggested by the induced structure of a hypersurface. Su…

2017-05-29abs ↗pdf ↗

Study geometric structures and their interactions under different metrics.

problem Understanding interactions between geometric structures under various metrics.
method Analyzing generalized polynomial structures and their behavior under different metrics on the generalized tangent bundle.
result Showed the commutation or anti-commutation of generalized polynomial structures forming triple structures.

We define a generalized almost para-Hermitian structure to be a commuting pair (F,J)(\mathcal{F},\mathcal{J}) of a generalized almost para-complex structure and a generalized almost complex structure with an adequate non-degeneracy condition. If the two structures are integrable the pair is called a generalized para-Kähle…

2015-03-04abs ↗pdf ↗

We characterize the Dirac structures that are parallel with respect to Gualtieri's canonical connection of a generalized Riemannian metric. On the other hand, we discuss Dirac structures that are images of generalized tangent structures. These structures turn out to be Dirac structures that, if seen as Lie algebroids, …

2011-05-30abs ↗pdf ↗

We construct a generalization of Courant algebroids which are classified by the third cohomology group H3(A,V)H^3(A,V), where AA is a Lie Algebroid, and VV is an AA-module. We see that both Courant algebroids and E1(M)\mathcal{E}^1(M) structures are examples of them. Finally we introduce generalized CR structures on a manif…

2008-11-28abs ↗pdf ↗

In this paper we define the notion of a generalized coKähler structure and prove that the product M1×M2M_{1}\times M_{2} of generalized contact metric manifolds (Mi,Φi,E±,i,Gi)(M_i, Φ_i,E_{\pm,i}, G_i), i=1,2 i=1, 2, where M1×M2M_{1}\times M_{2} is endowed with the product generalized complex structure induced from Φ1Φ_1 and Φ2Φ_2, is gener…

2015-02-25abs ↗pdf ↗

A Jacobi structure JJ on a line bundle LML\to M is weakly regular if the sharp map J:J1LDLJ^\sharp : J^1 L \to DL has constant rank. A generalized contact bundle with regular Jacobi structure possess a transverse complex structure. Paralleling the work of Bailey in generalized complex geometry, we find condition on a pair …

2018-06-27abs ↗pdf ↗

Let X be a compact Kahler manifold with a non-trivial holomorphic Poisson structure. Then there exist deformations of non-trivial generalized Kahler structures with one pure spinor on X. We prove that every Poisson submanifold of X is a generalized Kahler submanifold with respect to the deformed generalized Kahler stru…

2007-12-17abs ↗pdf ↗

Study integrability of specific geometric structures on odd Courant algebroids.

problem Characterize integrability of B_n-generalized structures on odd exact Courant algebroids.
method Characterize integrability in terms of existence of adapted generalized connections.
result Describe affine spaces of adapted generalized connections for integrable structures.

A generalized F-structure is a complex, isotropic subbundle EE of TcMTcMT_cM\oplus T^*_cM ($T_cM=TM\otimes_{\mathds{R}}\mathds{C}$ and the metric is defined by pairing) such that EEˉ=0E\cap\bar E^{\perp}=0. If EE is also closed by the Courant bracket, EE is a generalized CRF-structure. We show that a generalized F-structur…

2007-05-27abs ↗pdf ↗

The study characterizes real flag manifolds with invariant generalized almost complex structures.

problem Characterizing real flag manifolds with invariant generalized almost complex structures.
method Characterization through invariant BB-transformations and classification of structures.
result No GM2GM_2-maximal real flag manifolds admit integrable invariant generalized almost complex structures.

Extends corner structure study to general case, constructs normal Trans-Sasakian structures.

problem Extending corner structure study to general case without conditions.
method Extends corner structure to general case, constructs Trans-Sasakian structures from non-normal corner structures.
result Constructs normal Trans-Sasakian structures from non-normal corner structures.

An (I,J,K)-generalized Finsler structure on a 3-manifold is a generalization of a Finslerian structure, introduced in order to separate and clarify the local and global aspects in Finsler geometry making use of the Cartan's method of exterior differential systems. In this paper, we show that there is a close relation b…

2012-07-06abs ↗pdf ↗

In this paper we obtain a stability theorem of generalized Kahler structures with one pure spinor under small deformations of generalized complex structures. (This is analogous to the stability theorem of Kahler manifolds by Kodaira-Spencer.) We apply the stability theorem to a class of compact Kahler manifolds which a…

2007-05-17abs ↗pdf ↗

Deep generative models have shown promising results in generating realistic images, but it is still non-trivial to generate images with complicated structures. The main reason is that most of the current generative models fail to explore the structures in the images including spatial layout and semantic relations betwe…

2018-07-10abs ↗pdf ↗

Stable generalized complex structures on certain surfaces are constant.

problem Existence of stable generalized complex structures on ruled surfaces.
method Analysis of sphere bundles over surfaces of genus ≥2.
result Stable generalized complex structures on these surfaces are of constant type.

The notion of generalized almost paracontact structure on the generalized tangent bundle TMTMTM\oplus T^*M is introduced and its properties are investigated. The case when the manifold MM carries an almost paracontact metric structure is also discussed. Conditions for its transformed under a ββ- or a BB-field transfor…

2014-01-22abs ↗pdf ↗

New structures allow for self-crossing singularities, leading to new families of stable generalized complex manifolds.

problem Stable generalized complex structures in higher dimensions with self-crossing singularities.
method Extending stable generalized complex structures to include anticanonical sections with normal self-crossings.
result Construction of large families of stable generalized complex manifolds in four dimensions.

We give several equivalent characterizations of orthogonal subbundles of the generalized tangent bundle defined, up to B-field transform, by almost product and local product structures. We also introduce a pure spinor formalism for generalized CRF-structure and investigate the resulting decomposition of the de Rham ope…

2017-01-10abs ↗pdf ↗

On a smooth manifold M, generalized complex (generalized paracomplex) structures provide a notion of interpolation between complex (paracomplex) and symplectic structures on M. Given a complex manifold (M,j), we define six families of distinguished generalized complex or paracomplex structures on M. Each one of them in…

2013-09-27abs ↗pdf ↗

We introduce linear Dirac and generalized complex structures on Cartan geometries and give criteria for Dirac subalgebras of $\frkg\ltimes\frkg^*$ representing Dirac structures on a Cartan geometry. We prove that there is a bijection between the linear generalized structures on a torsion free Cartan geometry and the eq…

2012-04-26abs ↗pdf ↗

The paper explores SKT, balanced, and generalized Kähler structures on specific Lie groups.

problem Investigating invariant SKT, balanced, and generalized Kähler structures on compact quotients of almost nilpotent Lie groups.
method Characterization and classification of Hermitian almost nilpotent Lie algebras, study of structures under flows, and non-existence results.
result Construction of new compact SKT manifolds and examples of non-split generalized Kähler structures.

This is a short note on generalized G2G_2-structures obtained as a consequence of a TT-dual construction given in a previous work of the authors together with Leonardo Soriani. Given classical G2G_2-structure on certain seven dimensional manifolds, either closed or co-closed, we obtain integrable generalized G2G_2-str…

2017-09-26abs ↗pdf ↗

In this paper, we first discuss the relation between VB-Courant algebroids and E-Courant algebroids and construct some examples of E-Courant algebroids. Then we introduce the notion of a generalized complex structure on an E-Courant algebroid, unifying the usual generalized complex structures on even-dimensional manifo…

2017-05-28abs ↗pdf ↗

Introduces generalized almost plastic structures on manifolds.

problem Integrability of plastic structures on manifolds.
method Constructs a family of generalized almost plastic structures on pseudo-Riemannian manifolds with specific tensor fields and compatibility conditions.
result Characterizes the integrability of these structures with respect to a given affine connection.

This paper explores integrability conditions for generalized metrics and structures on manifolds.

problem Investigating integrability conditions for generalized metrics and structures on manifolds.
method Considered two notions of integrability: Courant bracket and connection-induced bracket. Provided sufficient criteria for integrability.
result Sufficient criteria for integrability of generalized metrics and structures are formulated.

The paper classifies invariant generalized complex structures on specific flag manifolds.

problem Classifying invariant generalized complex structures on partial flag manifolds.
method Proved that invariant generalized almost complex structures are constant in each component of the isotropy representation.
result All invariant generalized complex structures on partial flag manifolds with at most four isotropy summands are classified.

We define an almost--cosymplectic--contact structure which generalizes cosymplectic and contact structures of an odd dimensional manifold. Analogously, we define an almost--coPoisson--Jacobi structure which generalizes a Jacobi structure. Moreover, we study relations between these structures and analyse the associated …

2008-01-09abs ↗pdf ↗

ISL improves causal structure learning with invariant structures across different environments.

problem Improving causal structure discovery for better generalization and explainability.
method ISL splits data into environments, learns invariant structures, and selects optimal classifiers based on graph structures.
result ISL accurately discovers causal structures and outperforms alternative methods on synthetic and real-world datasets.