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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

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48 results for almost contact complex Riemannian

A Sasaki-like almost contact complex Riemannian manifold is defined as an almost contact complex Riemannian manifold which complex cone is a holomorphic complex Riemannian manifold. Explicit compact and non-compact examples are given. A canonical construction producing a Sasaki-like almost contact complex Riemannian ma…

2014-02-21abs ↗pdf ↗

Study of contact-complex Riemannian submersions in various manifold classes.

problem Characterizing submersions in specific manifold classes.
method Analyzing properties of O'Neill invariants and discussing integrability and minimality.
result Main properties of O'Neill invariants and integrability/minimality of fibres discussed.

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.

Study of Yamabe solitons on specific geometric manifolds.

problem Characterizing Yamabe solitons on almost contact complex Riemannian manifolds.
method Investigation of two cases: Sasaki-like and torse-forming potentials.
result Explicit examples and theoretical properties confirmed in 3D.

Study on solitons in complex Riemannian manifolds with specific properties.

problem Investigating solitons on specific types of complex Riemannian manifolds.
method Introduced and analyzed almost Riemann solitons on almost contact complex Riemannian manifolds with a vertical potential.
result Derived curvature properties and constructed an explicit example of dimension five.

New solitons defined for Sasaki-like almost contact complex Riemannian manifolds.

problem Characterizing new solitons in Sasaki-like almost contact complex Riemannian manifolds.
method Defined ββ-Ricci-Bourguignon-like almost solitons with special potential.
result Characterized geometrically and constructed examples of new solitons.

Study on Yamabe solitons on specific complex manifolds, focusing on torse-forming vector fields.

problem Exploring Yamabe solitons on a specific class of complex manifolds.
method Analyzing Yamabe solitons on almost contact complex Riemannian manifolds with a vertical torse-forming vector field.
result Explicit examples of 5-dimensional Lie groups characterized by the study.

We consider normal almost contact structures on a Riemannian manifold and, through their associated sections of an ad-hoc twistor bundle, study their harmonicity, as sections or as maps. We rewrite these harmonicity equations in terms of the Riemann curvature tensor and find conditions relating the harmonicity of the a…

2011-09-09abs ↗pdf ↗

Almost contact structures can be identified with sections of a twistor bundle and this allows to define their harmonicity, as sections or maps. We consider the class of nearly cosymplectic almost contact structures on a Riemannian manifold and prove curvature identities which imply the harmonicity of their parametrizin…

2011-09-13abs ↗pdf ↗

The paper defines quasi-isometry for almost contact metric manifolds and explores its properties.

problem Understanding quasi-isometry in almost contact metric manifolds.
method Definition and study of quasi-isometry for almost contact metric manifolds.
result Established a relation between scalar curvature and quasi-isometric constants.

The study examines conditions for weak nearly cosymplectic manifolds to split into products.

problem Understanding the curvature and topology of weak nearly cosymplectic manifolds.
method Analyzes the conditions for splitting and characterizes specific manifolds.
result Conditions for weak nearly cosymplectic manifolds to become Riemannian products are identified.

The paper explores generalized Riemannian manifolds with weak metric structures.

problem Understanding weak metric structures on generalized Riemannian manifolds.
method Study of generalized metric connections, weak metric structures, and skew-symmetric torsion.
result Generalized Riemannian manifolds can be split into nearly Kähler manifolds.

The paper connects complex contact structures to specific types of almost contact 3-structures.

problem Understanding the relationship between complex contact structures and almost contact 3-structures.
method Proving that every complex contact structure gives rise to a distinguished almost contact metric 3-structure.
result The paper provides new examples of manifolds with specific contact and almost contact structures.

We study 5-dimensional Riemannian manifolds that admit an almost contact metric structure. We classify these structures by their intrinsic torsion and review the literature in terms of this scheme. Moreover, we determine necessary and sufficient conditions for the existence of metric connections with vectorial, totally…

2011-10-17abs ↗pdf ↗

Study of abelian structures on odd-dimensional Lie algebras and their geometric properties.

problem Characterizing abelian structures on odd-dimensional Lie algebras.
method Introducing and analyzing abelian almost contact and almost 3-contact structures, and their compatibility conditions.
result Classification of 5-dimensional Sasakian Lie algebras and 7-dimensional abelian almost 3-contact Lie algebras.

In this paper we generalize the main notions from the geometry of (almost) contact manifolds in the category of Lie algebroids. Also, using the framework of generalized geometry, we obtain an (almost) contact Riemannian Lie algebroid structure on a vertical Liouville distribution over the big-tangent manifold of a Riem…

2015-07-04abs ↗pdf ↗

The paper presents the Einstein connection for nonsymmetric pseudo-Riemannian manifolds.

problem The challenge is to define the Einstein connection for nonsymmetric pseudo-Riemannian manifolds.
method The approach involves using a weak almost contact structure and a linear connection with torsion.
result Explicit formulas for the Einstein connection are provided.

The paper connects complex spacetimes to twistor spaces and finds an almost contact structure.

problem Understanding the geometry of complex spacetimes and their relation to twistor spaces.
method Using a correspondence between 5D complex spacetimes and 4D twistor spaces, the paper constructs almost contact structures.
result A 5-dimensional K-contact manifold can be derived from the Ren-Wang twistor space.

The paper defines a new connection on sub-Riemannian manifolds and explores conditions for almost quasi-Sasakian manifolds to be Einstein.

problem Exploring new connections and conditions for specific types of manifolds.
method Defining a skew-symmetric connection and studying its properties on sub-Riemannian manifolds, and examining conditions for almost quasi-Sasakian manifolds to be Einstein.
result Sufficient conditions are found for an almost quasi-Sasakian manifold to be an Einstein manifold.

In monograph of D. E. Blair "Riemannian geometry of contact and symplectic manifolds" and in the paper of S. Zamkovoy "Canonical connections on paracontact manifolds", the curvature identities respectively for contact and paracontact metric manifold are proved. We obtain the curvature identity in the wider class of man…

2012-09-21abs ↗pdf ↗

Study on umbilical submanifolds in specific geometric spaces.

problem Characterizing curvature properties of umbilical submanifolds.
method Analyzing totally and screen totally umbilical half lightlike submanifolds in almost contact B-metric manifolds.
result Curvature properties of these submanifolds were studied and characterized.

Paper finds previous work on submanifolds incorrect.

problem Incorrect definition of semi-invariant submanifolds.
method Examined previous work's definition and found it flawed.
result Previous results on semi-invariant submanifolds are invalid.

We consider manifolds endowed with a contact pair structure. To such a structure are naturally associated two almost complex structures. If they are both integrable, we call the structure a normal contact pair. We generalize the Morimoto's Theorem on product of almost contact manifolds to flat bundles. We construct som…

2008-05-02abs ↗pdf ↗

The study explores δ-almost gradient Yamabe solitons on pseudo-Riemannian manifolds.

problem Characterizing δ-almost gradient Yamabe solitons on pseudo-Riemannian manifolds.
method Analyzing δ-almost Yamabe solitons within the framework of para-contact metric manifolds, proving properties and conditions for solitons.
result Characterization of δ-almost gradient Yamabe solitons on K-paracontact metric manifolds.

We introduce a generalization of structured manifolds as the most general Riemannian metric g associated to an affinor (tensor field of (1,1)-type) F and initiate a study of their semi-invariant submanifolds. These submanifolds are generalization of CR-submanifolds of almost complex geometry and semi-invariant submanif…

2011-09-03abs ↗pdf ↗

The paper presents the Einstein connection for nonsymmetric pseudo-Riemannian manifolds with specific torsion conditions.

problem Tackles the Einstein connection in nonsymmetric pseudo-Riemannian manifolds with non-degenerate skew-symmetric tensor.
method Explicitly presents the Einstein connection for nonsymmetric pseudo-Riemannian manifolds with f2f^2-torsion condition.
result Reduces to M.Prvanović's solution in the almost Hermitian case.

Study of intrinsic sub-Laplacian for hypersurfaces in contact sub-Riemannian manifolds.

problem Characterizing the intrinsic sub-Laplacian for hypersurfaces in contact sub-Riemannian manifolds.
method Construction and analysis of the intrinsic sub-Laplacian using Riemannian approximations and stochastic processes.
result The intrinsic sub-Laplacian is stochastically complete, ensuring the process does not hit characteristic points.

For an almost contact metric manifold NN, we find conditions for which either the total space of an S1S^1-bundle over NN or the Riemannian cone over NN admits a strong Kähler with torsion (SKT) structure. In this way we construct new 6-dimensional SKT manifolds. Moreover, we study the geometric structure induced on …

2009-09-22abs ↗pdf ↗

We study 5-dimensional Riemannian manifolds that admit an almost contact metric structure. In particular, we generalize the class of quasi-Sasaki manifolds and characterize these structures by their intrinsic torsion. Among other things, we see that these manifolds admit a unique metric connection that is compatible wi…

2012-11-12abs ↗pdf ↗

An almost contact metric structure is parametrized by a section of an associated homogeneous fibre bundle, and conditions for this to be a harmonic section, and a harmonic map, are studied. These involve the characteristic vector field, and the almost complex structure in the contact subbundle. Several examples are giv…

2006-02-23abs ↗pdf ↗

The paper explores new connections in non-symmetrical gravitational theory using weak metric structures.

problem Investigating linear connections in non-symmetrical gravitational models.
method Study of generalized Riemannian manifolds with weak metric structures and connections satisfying specific conditions.
result Proved properties of connections and structures in generalized Riemannian manifolds.

We continue our study of contact structures on manifolds of dimension at least five using complex surgery theory. We show that in each dimension 2q+1 > 3 there are 'maximal' almost contact manifolds to which there is a Stein cobordism from any other (2q+1)-dimensional contact manifold. We show that the product M x S^2 …

2014-09-26abs ↗pdf ↗