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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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59117176234 · Jun 202019922001200920172026
48 results for Sphere metrics

We prove the existence of an abundance of new Einstein metrics on odd dimensional spheres including exotic spheres, many of them depending on continuous parameters. The number of families as well as the number of parameter grows double exponentially with the dimension. Our method of proof uses Brieskorn-Pham singularit…

2003-09-24abs ↗pdf ↗

Study classifies metrics on a twice-punctured sphere, proving Delaunay metrics are complete.

problem Classifying metrics on a twice-punctured sphere.
method Analyzes Delaunay metrics and proves a sharp conformal factor bound.
result Proves that most conformal flat metrics on a twice-punctured sphere are Delaunay metrics.

Researchers found all invariant contact structures on tangent sphere bundles of compact symmetric spaces.

problem Identifying all invariant contact metric structures on tangent sphere bundles of compact rank-one symmetric spaces.
method Explicitly obtained all structures, distinguishing K-contact, Sasakian, and 3-Sasakian structures.
result There is a unique Sasakian-Einstein metric on tangent sphere bundles of spheres and real projective spaces.

We study metric spaces homeomorphic to the 2-sphere, and find conditions under which they are quasisymmetrically homeomorphic to the standard 2-sphere. As an application of our main theorem we show that an Ahlfors 2-regular, linearly locally contractible metric 2-sphere is quasisymmetrically homeomorphic to the standar…

2001-07-24abs ↗pdf ↗

We construct a metrical framed structure on the tensor bundle of a Riemannian manifold equipped with a Cheeger-Gromoll type metric and by restricting this structure to the tensor sphere bundle, we obtain an almost metrical paracontact structure on the tensor sphere bundle. Moreover, we show that the tensor sphere bundl…

2013-06-08abs ↗pdf ↗

The paper defines a new structure on tangent sphere bundles and characterizes their properties.

problem Characterizing properties of tangent sphere bundles with contact pseudo-metric structures.
method Introduced a contact pseudo-metric structure on TεMT_\varepsilon M and proved manifold properties based on constant sectional curvature.
result The tangent sphere bundle TεMT_{\varepsilon}M is (κ,μ)(κ, μ)-contact pseudo-metric manifold if and only if the manifold MM has constant sectional curvature.

We prove that all smooth sphere bundles that admit fiberwise 1/4-pinched metrics are induced bundles of vector bundles, so their structure groups reduce from the diffeomorphism group of the sphere to the orthogonal group. This result implies the existence of many smooth n-sphere bundles over a k-sphere that do not supp…

2015-05-14abs ↗pdf ↗

Study of spheres and circles on a manifold with a specific metric structure.

problem Understanding geometric objects on a manifold with a skew-circulant structure.
method Analyzing hyper-spheres, spheres, and circles in a tangent space of a 4D manifold with a skew-circulant tensor structure.
result Characterization of geometric objects under an indefinite metric.

Characterizes invariant contact metric structures on tangent sphere bundles of compact symmetric spaces.

problem Identifying invariant contact metric structures on tangent sphere bundles of compact symmetric spaces.
method Characterization through invariant Riemannian metrics and Killing vector fields.
result A family of invariant contact metric structures is obtained on tangent sphere bundles of compact symmetric spaces with rank greater than or equal to two.

We construct non-trivial continuous isospectral deformations of Riemannian metrics on the ball and on the sphere in Rn\R^n for every n9n\geq 9. The metrics on the sphere can be chosen arbitrarily close to the round metric; in particular, they can be chosen to be positively curved. The metrics on the ball are both Diric…

2000-05-16abs ↗pdf ↗

The paper constructs metrics on spheres with families of minimal hypersurfaces.

problem Finding Riemannian metrics on spheres with specific families of minimal hypersurfaces.
method Used Nash-Moser Inverse Function Theorem in the tame maps setting.
result Generalized Guillemin's theorem for Zoll families of minimal hypersurfaces.

In this paper we use the relationship between conformal metrics on the sphere and horospherically convex hypersurfaces in the hyperbolic space for giving sufficient conditions on a conformal metric to be radial under some constrain on the eigenvalues of its Schouten tensor. Also, we study conformal metrics on the spher…

2008-08-19abs ↗pdf ↗

Study on Ricci flow of invariant metrics on spheres, finding new ancient solutions.

problem Analyzing the Ricci flow of Sp(n+1)-invariant metrics on spheres.
method Determine forward and ancient solutions, classify them, and classify their behavior under flow.
result Exhibit a new one-parameter family of ancient solutions on spheres with larger isometry groups.

The invariant metric affine connections on Berger spheres which are Einstein with skew torsion are determined in both Riemannian and Lorentzian signature. Expressions of such connections are explicitly given. In particular, every Berger sphere with Lorentzian signature admits invariant metric affine connections Einstei…

2017-09-25abs ↗pdf ↗

The study finds conditions for minimal spheres into ellipsoids using eigenfunctions.

problem Conditions for branched minimal immersions of spheres into ellipsoids to be embedded.
method Using eigenfunctions with respect to a critical metric, the study provides sufficient conditions for embeddings and constructions of non-planar minimal spheres.
result Conditions for embeddings and constructions of non-planar minimal spheres using eigenfunctions.

Sharp bounds found on shortest geodesic on punctured spheres.

problem Finding the shortest closed geodesic on punctured spheres.
method Sharp curvature-free upper bounds expressed in terms of area, extremal metrics described.
result Optimal bounds for spheres with up to four ends, extended to larger numbers of punctures.

The study examines moduli spaces of metrics with positive Ricci or non-negative sectional curvature on sphere bundles.

problem Classifying and understanding moduli spaces of metrics with specific curvature properties on sphere bundles.
method Analyzing total spaces of S7S^7-bundles over S8S^8 and quotients of Milnor and Shimada spheres.
result The moduli space of metrics has infinitely many path components.

We study metrics on conic 2-spheres when no Einstein metrics exist. In particular, when the curvature of a conic metric is positive, we obtain the best curvature pinching constant. We also show that when this best pinching constant is approached, the conic 2-sphere has an explicit Gromov-Hausdorff limit. This is a gene…

2015-06-19abs ↗pdf ↗

We establish an explicit expression for the smallest non-zero eigenvalue of the Laplace--Beltrami operator on every homogeneous metric on the 3-sphere, or equivalently, on SU(2) endowed with left-invariant metric. For the subfamily of 3-dimensional Berger spheres, we obtain a full description of their spectra. We also …

2018-01-12abs ↗pdf ↗

Study finds non-uniqueness in sphere metrics with constant fractional curvature.

problem Non-uniqueness of metrics with constant positive fractional curvature on spheres.
method Bifurcation techniques applied to non-local equations with critical non-linearity.
result Non-uniqueness results for complete metrics on SnSkS^n \setminus S^k.

Uniform convergence of metrics on vortex moduli space in Bradlow limit.

problem Understanding the geometry of vortex moduli spaces.
method Proof of uniform convergence of metrics using normalized L2L^2 metric and Fubini-Study metric.
result Establishes the Fubini-Study metric as the limit of the normalized L2L^2 metric in the Bradlow limit.

In this paper we demonstrate the existence of Sasakian-Einstein structures on certain 2-connected rational homology 7-spheres. These appear to be the first non-regular examples of Sasakian-Einstein metrics on simply connected rational homology spheres. We also briefly describe the rational homology 7-spheres that admit…

2001-08-16abs ↗pdf ↗

In a recent article the first three authors proved that in dimension 4m+14m+1 all homotopy spheres that bound parallelizable manifolds admit Einstein metrics of positive scalar curvature which, in fact, are Sasakian-Einstein. They also conjectured that all such homotopy spheres in dimension 4m1,m24m-1, m\geq2 admit Sasakian-…

2003-11-17abs ↗pdf ↗

In this paper we characterize compact extended Ptolemy metric spaces with many circles up to Möbius equivalence. This characterization yields a Möbius characterization of the nn-dimensional spheres SnS^n and hemispheres S+nS^n_+ when endowed with their chordal metrics. In particular, we show that every compact extended…

2010-08-19abs ↗pdf ↗

The paper studies rigid sphere packings on 3D manifolds with boundary.

problem Investigating rigid sphere packings on 3D manifolds with boundary.
method Introducing generalized sphere packings, proving rigidity, introducing combinatorial curvature flows.
result Generalized sphere packing metrics are determined by combinatorial scalar curvature.