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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.

169,341 papers · 148 categories

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5101419 · Jul 202619922001200920182026
48 results for Killing 2-form

Study classifies manifolds with nonpositive curvature and finds conformal Killing forms.

problem Characterizing manifolds with nonpositive curvature operator.
method Classification and vanishing theorems for conformal Killing forms.
result Classification and vanishing results for conformal Killing forms.

Study invariant CKY 2-forms on 5D Lie groups, classifying and determining their properties.

problem Classifying and understanding CKY 2-forms on 5D Lie groups.
method Classification and analysis of 5D metric Lie algebras with CKY tensors.
result First examples of CKY 2-forms on metric Lie algebras without Sasakian structures.

Motivated by the possible characterization of Sasakian manifolds in terms of twistor forms, we give the complete classification of compact Riemannian manifolds carrying a Killing vector field whose covariant derivative (viewed as a 2-form) is a twistor form.

2005-09-28abs ↗pdf ↗

On a closed, connected Riemannian manifold with a Kähler foliation of codimension q=2mq=2m, any transverse Killing r (2)r\ (\geq 2)-form is parallel (S. D. Jung and M. J. Jung [\ref{JJ2}], Bull. Korean Math. Soc. 49 (2012)). In this paper, we study transverse conformal Killing forms on Kähler foliations and prove that if th…

2014-08-29abs ↗pdf ↗

Classifies ambitoric 4-orbifolds with completeness assumptions.

problem Classifying ambitoric 4-orbifolds with completeness assumptions.
method Developed tools to classify regular ambitoric 4-orbifolds with completeness assumptions.
result Proved a partial classification of compact Riemannian 4-manifolds with a Killing 2-form.

Study Killing forms on 2-step nilpotent Lie groups, finding their structure and dimensions.

problem Characterize Killing forms on 2-step nilpotent Lie groups with a Riemannian metric.
method Analyze left-invariant Killing k-forms on simply connected 2-step nilpotent Lie groups, decomposing into irreducible factors.
result The space of Killing k-forms is at most one-dimensional for k=2 or k=3.

Given a maximally non-integrable 2-distribution D{\mathcal D} on a 5-manifold MM, it was discovered by P. Nurowski that one can naturally associate a conformal structure [g]D[g]_{\mathcal D} of signature (2,3) on MM. We show that those conformal structures [g]D[g]_{\mathcal D} which come about by this construction are c…

2009-08-04abs ↗pdf ↗

Charge measurements for instantons and gravitational perturbations.

problem Evaluating charges in Hermitian non-Kähler Einstein 4-manifolds and their perturbations.
method Evaluation of charges via Killing spinors and perturbation analysis of gravitational instantons.
result Generic gravitational perturbations admit a closed 2-form measuring the charge change.

Geometric correspondence between quadrics and their twistor spaces for null foliations.

problem Constructing null foliations in complex Euclidean space.
method Mapping null foliations to complex submanifolds of twistor space.
result Local foliations can be constructed using complex submanifolds of twistor space.

Study compares two pseudo-Kähler structures on a specific mathematical component.

problem Comparing two pseudo-Kähler structures on the SL(3,R)\mathrm{SL}(3,\mathbb{R})-Hitchin component.
method Examined Rungi-Tamburelli's ωfω_f and Goldman's ωGω_G forms, and aligned Killing forms.
result Rungi-Tamburelli's semi-pseudo-Kähler structure is non-degenerate and matches another structure after normalization.

In some other context, the question was raised how many nearly Kähler structures exist on the sphere §6§^6 equipped with the standard Riemannian metric. In this short note, we prove that, up to isometry, there exists only one. This is a consequence of the description of the eigenspace to the eigenvalue λ=12λ= 12 of the L…

2005-09-07abs ↗pdf ↗

Study local equivalence of Riemannian submersions using differential invariants.

problem Local equivalence problem for Riemannian submersions under fiber-preserving isometries.
method Analysis of differential invariants for orbit submersions induced by a Killing field.
result Explicit formulas for AA and HH in terms of base data (gˉ,φ,Ω)(\bar g,\varphi,Ω) and equivalence criterion.

We study the relationship between multiplicative 2-forms on Lie groupoids and linear 2-forms on Lie algebroids, which leads to a new approach to the infinitesimal description of multiplicative 2-forms and to the integration of twisted Dirac manifolds.

2009-11-02abs ↗pdf ↗

Study magnetic fields on special Lie groups, proving non-existence of certain types.

problem Existence of closed 2-forms with specific properties on non-singular 2-step nilpotent Lie groups.
method Analyzing left-invariant magnetic fields on 2-step nilpotent Lie groups, proving non-existence and existence results.
result Strong obstruction and non-existence of closed 2-forms of type II on non-singular Lie algebras.

The paper constructs non-convergent solutions to Vafa-Witten equations with specific harmonic 2-form limits.

problem Constructing solutions to Vafa-Witten equations with non-zero mass term.
method Constructs divergent sequences of solutions, renormalizes them, and defines harmonic 2-form data sets.
result Defines an 'interesting' harmonic 2-form data set with specific properties.

The paper classifies topological properties of specific geometric forms on manifolds.

problem Classifying topological properties of closed G~2\widetilde{\mathrm{G}}_2, SL(3;C)\mathrm{SL}(3;\mathbb{C}) and SL(3;R)2\mathrm{SL}(3;\mathbb{R})^2 forms.
method Algebraic and topological techniques, including characteristic classes and obstruction theory, with recent hh-principles.
result Complete classification of closed SL(3;C)\mathrm{SL}(3;\mathbb{C}) forms up to homotopy.

We will prove a Moser-type theorem for self-dual harmonic 2-forms on closed 4-manifolds, and use it to classify local forms on neighborhoods of singular circles on which the 2-form vanishes. Removing neighborhoods of the circles, we obtain a symplectic manifold with contact boundary - we show that the contact form on e…

1997-05-30abs ↗pdf ↗

The paper studies symplectic structures on character varieties of Sasakian threefolds.

problem Character varieties of Sasakian threefolds and their symplectic structures.
method Constructing a natural algebraic 2-form and showing its properties.
result The restriction of the 2-form to the space of irreducible SU(r) homomorphisms is symplectic.

The paper extends the classification of bi-invariant 2-forms to infinite-dimensional Lie groups.

problem Classifying bi-invariant 2-forms on infinite-dimensional Lie groups.
method Generalized the classification from compact Lie groups to arbitrary finite-dimensional Lie groups and then to Milnor regular infinite-dimensional Lie groups.
result The classification of bi-invariant 2-forms extends to all Milnor regular infinite-dimensional Lie groups.

Killing-Yano and conformal Killing-Yano superalgebras are rigid in constant curvature manifolds.

problem Understanding the rigidity of Killing-Yano and conformal Killing-Yano superalgebras in constant curvature manifolds.
method Defining Z\mathbb{Z}-gradations and filtrations, showing trivial second cohomology groups, and proving non-deformability.
result Killing-Yano and conformal Killing-Yano superalgebras are rigid and correspond to geometric invariants of constant curvature manifolds.

Generalizes Lie algebra of conformal Killing vector fields to conformal Killing-Yano forms.

problem Understanding the algebraic structure of conformal Killing-Yano forms.
method Proposes a new Lie bracket and shows graded Lie algebra properties in constant and Einstein manifolds.
result Conformal Killing-Yano forms form a graded Lie algebra in specific manifolds.

New method finds global Lagrangians for variational systems.

problem Constructing global variational principles for variational systems.
method Analyzing Lepage 2-forms and finding global Lagrangians for systems defined by homogeneous functions of degree \(c eq 0, 1\).
result Locally variational systems defined by homogeneous functions of degree \(c eq 0, 1\) are globally variational.

This paper is concerned with symmetries of closed multiplicative 2-forms on Lie groupoids and their infinitesimal counterparts. We use them to study Lie group actions on Dirac manifolds by Dirac diffeomorphisms and their lifts to presymplectic groupoids, building on recent work of Fernandes-Ortega-Ratiu \cite{FOR} on P…

2011-12-21abs ↗pdf ↗

We introduce the notion of a hamiltonian 2-form on a Kaehler manifold and obtain a complete local classification. This notion appears to play a pivotal role in several aspects of Kaehler geometry. In particular, on any Kaehler manifold with co-closed Bochner tensor, the (suitably normalized) Ricci form is hamiltonian, …

2002-02-26abs ↗pdf ↗