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arXiv research

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.

168,695 papers · 148 categories

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57114170227 · Jun 202619922001200920172026
48 results for 4n-dimensional manifolds

Study curvature operators in 4n-dimensional manifolds, finding new conformal invariants.

problem Analyzing curvature operators in oriented Riemannian 4n-manifolds.
method Examining finite systems of hafnian identities in eigenvalues, focusing on locally conformally flat cases.
result Discovering a new conformal invariant in dimensions 4n, related to nonnegativity of Euler characteristic.

Study on symplectic semi-characteristic using cohomology and vector fields.

problem Defining and calculating the symplectic semi-characteristic of symplectic manifolds.
method Defined using even-degree primitive cohomology and proved a counting formula using vector fields.
result Established a counting formula for symplectic semi-characteristic and derived vanishing properties.

In this paper, firstly, for some 4n4n-dimensional almost complex manifolds Mi, 1iαM_{i}, ~1\le i \le α, we prove that (i=1αMi)(α1)CP2n\left(\sharp_{i=1}^α M_{i}\right) \sharp (α{-}1) \mathbb{C} P^{2n} must admits an almost complex structure, where αα is a positive integer. Secondly, for a 2n2n-dimensional almost complex manifold MM, we…

2018-08-22abs ↗pdf ↗

A Hermitian metric on a complex manifold is called strong Kähler with torsion (SKT) if its fundamental 2-form ωω is ˉ\partial \bar \partial-closed. We review some properties of strong KT metrics also in relation with symplectic forms taming complex structures. Starting from a 2n2n-dimensional SKT Lie algebra $\mathfr…

2011-04-08abs ↗pdf ↗

We show that the geometry of 4n4n-dimensional quaternionic Kähler spaces with a locally free Rn+1\mathbb{R}^{n+1}-action admits a Gibbons-Hawking-like description based on the Galicki-Lawson notion of quaternionic Kähler moment map. This generalizes to higher dimensions a four-dimensional construction, due to Calderbank …

2019-01-31abs ↗pdf ↗

We study the hypersymplectic spaces obtained as quotients of flat hypersymplectic space R^{4d} by the action of a compact Abelian group. These 4n-dimensional quotients carry a multi-Hamilitonian action of an n-torus. The image of the hypersymplectic moment map for this torus action may be described by a configuration o…

2004-04-30abs ↗pdf ↗

We give a procedure for constructing an 8n8n-dimensional HKT Lie algebra starting from a 4n4n-dimensional one by using a quaternionic representation of the latter. The strong (respectively, weak, hyper-Kähler, balanced) condition is preserved by our construction. As an application of our results we obtain a new compact…

2008-05-15abs ↗pdf ↗

A well-known property of the signature of closed oriented 4n-dimensional manifolds is Novikov additivity, which states that if a manifold is split into two manifolds with boundary along an oriented smooth hypersurface, then the signature of the original manifold equals the sum of the signatures of the resulting manifol…

2009-11-19abs ↗pdf ↗

We study type one generalized complex and generalized Calabi--Yau manifolds. We introduce a cohomology class that obstructs the existence of a globally defined, closed 2-form which agrees with the symplectic form on the leaves of the generalized complex structure, the twisting class. We prove that in a compact, type on…

2016-11-14abs ↗pdf ↗

The paper develops quaternionic toric geometry and classifies local actions.

problem Classifying local quaternionic torus actions on manifolds.
method Develops local QnQ^n-actions, introduces invariants, and studies tetraplectic structures.
result Classifies local quaternionic torus actions up to homeomorphism.

We consider a general 4n-dimensional quaternionic Kahler geometry with a free action of the torus T^(n+1). The toric action lifts onto the Swann bundle of the quaternionic Kahler space to a tri-holomorphic action that commutes with the standard H* action on the bundle. By matching Pedersen and Poon's generalized Gibbon…

2008-11-23abs ↗pdf ↗

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.

:Let G be a group together with an descending nested sequence of normal subgroups G=G_0, G_1, G_2 G_3, ... of finite index [G:G_k] such the intersection of the G_k-s is the trivial group. Let (X,Y) be a compact 4n-dimensional Poincare' pair and p: (\bar{X},\bar{Y}) \to (X,Y) be a G-covering, i.e. normal covering with G…

2001-10-31abs ↗pdf ↗

This paper studies geometric structures on manifolds with specific symplectic properties.

problem Understanding geometric structures on manifolds with quaternionic skew-Hermitian properties.
method Equivalent definitions, intrinsic torsion, classification of geometries, explicit connections.
result Classification of symmetric spaces with invariant torsion-free structures.

A complex symplectic structure on a Lie algebra $\lie h$ is an integrable complex structure JJ with a closed non-degenerate (2,0)(2,0)-form. It is determined by JJ and the real part ΩΩ of the (2,0)(2,0)-form. Suppose that $\lie h$ is a semi-direct product $\lie g\ltimes V$, and both $\lie g$ and VV are Lagrangian with re…

2010-04-19abs ↗pdf ↗

Study Sp(n)Sp(n)-orbits in complex and ΣΣ-complex subspaces of Hermitian quaternionic vector spaces.

problem Characterize Sp(n)Sp(n)-orbits in Grassmannians of complex and ΣΣ-complex subspaces.
method Decompose subspaces into 4-dimensional complex addends and 2-dimensional totally complex subspace. Use properties of isoclinic subspaces and principal angles.
result Determine full set of invariants for Sp(n)Sp(n)-orbits in GrR(2k,4n)Gr^\R(2k,4n).

Study Sp(n)Sp(n)-orbits of isoclinic subspaces in real Grassmannians.

problem Understanding Sp(n)Sp(n)-orbits of isoclinic subspaces in real Grassmannians.
method Investigate isoclinic subspaces in GR(k,4n)G^\R(k,4n) using Hermitian quaternionic structure and admissible hypercomplex basis.
result Angles of isoclinicity and invariants (ξ,χ,η,Δ)(ξ,χ,η, Δ) determine Sp(n)Sp(n)-orbit of isoclinic subspaces.

In 1972, K. Kenmotsu studied a class of almost contact Riemannian manifolds. Later, such a manifold was called a Kenmotsu manifold. This paper, we studied Kenmotsu manifolds with (2n+s)(2n+s)-dimensional ss-contact metric manifold and this manifold, we have called generalized Kenmotsu manifolds. Necessary and sufficient c…

2014-06-04abs ↗pdf ↗

Study on a new type of manifolds that generalize almost C-manifolds.

problem Understanding weak nearly C-manifolds and their properties.
method Analyzing conditions for local Riemannian product structures and characterizing specific dimensions.
result Conditions for a weak nearly C-manifold to become locally a Riemannian product and characterization of specific dimensions.

Stabilized convex symplectic manifolds are equivalent to flexible Weinstein manifolds.

problem Understanding the equivalence between stabilized convex symplectic manifolds and flexible Weinstein manifolds.
method Analyzing the homotopy type and symplectic properties of the manifolds.
result Stabilized convex symplectic manifolds are symplectomorphic to flexible Weinstein manifolds.

A selfsimiar manifold is a Riemannian manifold (M,g)\left(M,g\right) endowed with a homothetic vector field ξξ. We characterize global selfsimilar manifolds and describe the structure of local selfsimilar manifolds. We prove that any selfsimilar manifold with a potential homothetic vector field is a conical Riemannian ma…

2019-08-05abs ↗pdf ↗

The study provides a structure theorem for a new class of noncompact 3-manifolds.

problem Understanding a new class of noncompact 3-manifolds.
method Proved a structure theorem for irreducible open graph manifolds.
result A canonical 'reduced' decomposition of irreducible open graph manifolds along embedded, incompressible 2-tori.

The paper studies extended quasi-Einstein manifolds with special geometric properties and solitons.

problem Exploring new types of manifolds in general relativity.
method Generalization of existing manifolds and construction of specific examples.
result Existence and properties of extended quasi-Einstein manifolds with solitons.

Conditions for flat manifolds as cusp cross-sections in arithmetic hyperbolic manifolds.

problem Determining when a flat manifold can be a cusp cross-section in arithmetic hyperbolic manifolds.
method Analyzing rational representations of holonomy groups and quasi-arithmetic manifolds.
result Conditions for a flat manifold to appear as a cusp cross-section in every commensurability class of arithmetic hyperbolic manifolds.

Classifies 3-manifolds from simplified (2,0)-trisections of 4-manifolds.

problem Classifying 3-manifolds from simplified (2,0)-trisections of 4-manifolds.
method Classifies vertical 3-manifolds as preimages of arcs on the plane for simplified (2,0)-trisection maps.
result Each 6-tuple of vertical 3-manifolds determines the source 4-manifold uniquely up to orientation reversing diffeomorphisms.

Study on 3D manifolds with specific tensor structures and their properties.

problem Characterizing 3D Riemannian manifolds with tensor structures.
method Investigation of locally conformal Riemannian product manifolds and their associated structures.
result Conditions for additional structures to be parallel and properties of almost Einstein and Einstein manifolds.

New manifold type PNDP-manifold defined with Einstein warped product structure.

problem Defining manifolds with non-standard dimensions.
method Einstein warped product manifold with special base and fiber structures.
result PNDP-manifolds are Einstein warped product manifolds with specific base and fiber properties.

The paper explores F-manifolds and metrics, constructing canonical structures.

problem Understanding relationships between F-manifolds and metrics.
method Construction of canonical flat F-manifolds and homogeneous Riemannian F-manifolds.
result Construction of a canonical flat F-manifold associated to an arbitrary Riemannian F-manifold.

We introduce a new general class of metric f-manifolds which we call (nearly) trans-S-manifolds and includes S- manifolds, C-manifolds, s-th Sasakian manifolds and generalized Kenmotsu manifold studied previously. We prove their main properties and we present many examples which justify their study.

2016-12-21abs ↗pdf ↗

The study provides homological characterizations for QQ-manifolds and l2l_2-manifolds.

problem Density of maps in characterizing QQ-manifolds and l2l_2-manifolds.
method Investigates weakening the density of ZnZ_n-maps and ZZ-maps to homological maps.
result Obtains homological characterizations for QQ-manifolds and l2l_2-manifolds.

A locally conformally Kähler (LCK) manifold MM is one which is covered by a Kähler manifold M~\tilde M with the deck transform group acting conformally on M~\tilde M. If MM admits a holomorphic flow, acting on M~\tilde M conformally, it is called a Vaisman manifold. Neither the class of LCK manifolds nor that of Vais…

2004-07-13abs ↗pdf ↗

Study weak quasi contact metric manifolds to generalize K-contact and Sasakian manifolds criteria.

problem Generalize K-contact and Sasakian manifolds criteria using weak quasi contact metric manifolds.
method Study weak quasi contact metric manifolds and generalize theorems for K-contact and Sasakian manifolds.
result Provide new criterions for K-contact and Sasakian manifolds in terms of curvature tensor and geometric objects.

The study classifies Kähler-Frobenius manifolds and their properties.

problem Classifying Kähler-Frobenius manifolds and understanding their structure.
method Using Topological Quantum Field Theory and Frobenius manifold theory.
result All flat compact Kähler manifolds are Frobenius manifolds and are classified.

Study geodesics on infinite-dimensional manifolds using Finsler structures.

problem Geodesics on Fréchet manifolds of Riemannian metrics.
method Establish Riemann-Finsler structures, prove existence and minimality of geodesics, derive Euler-Lagrange equations.
result Geodesics on Fréchet manifolds of Riemannian metrics are length minimizing and satisfy Euler-Lagrange equations.