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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.

168,742 papers · 148 categories

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326597129 · May 202619922001200920172026
48 results for 2-convex surfaces

The paper proves convexity of certain solitons and expanders in high dimensions.

problem Proving convexity of specific solitons and expanders in Rn+1\mathbb{R}^{n+1}.
method Inspired by Spruck-Xiao and Derdziński, the paper uses geometric analysis to prove convexity.
result The paper proves the convexity of complete 2-convex translating and expanding solitons and expanders in Rn+1\mathbb{R}^{n+1} for n3n\geq 3.

We prove that any translating soliton for the mean curvature flow which is noncollapsed and uniformly 2-convex must be the rotationally symmetric bowl soliton. In particular, this proves a conjecture of White and Wang, in the 2-convex case in arbitrary dimension.

2014-08-13abs ↗pdf ↗

In this article, we use the recently developed mean curvature flow with surgery for 2 convex hypersurfaces to prove several isotopy existence and finally extrinsic finiteness results (in the spirit of Cheeger's compactness theorem) for the space of 2 convex hypersurfaces in Rn+1\mathbb{R}^{n+1}.

2017-05-09abs ↗pdf ↗

We give a new proof for the existence of mean curvature flow with surgery of 2-convex hypersurfaces in RNR^N, as announced in arXiv:1304.0926. Our proof works for all N3N \geq 3, including mean convex surfaces in R3R^3. We also derive a priori estimates for a more general class of flows in a local and flexible setting.

2014-04-08abs ↗pdf ↗

Level set flow's singularities are type I under 2-convexity, leading to specific curvature blow-up rates.

problem Understanding the nature and behavior of singularities in level set flow.
method Analytical approach using Lojasiewicz inequality and curvature blow-up rates.
result The arrival time is C2C^{2} near a critical point if and only if it satisfies a Lojasiewicz inequality.

The paper strengthens a singularity theorem in General Relativity.

problem Proving conditions under which spacetime is incomplete or has specific geometric structures.
method Improving a previous theorem by Galloway and Ling, the paper introduces new conditions for spacetime properties.
result Conditions for spacetime to be past null geodesically incomplete, or have specific geometric structures.

The paper connects convex functions to p-subharmonic functions and proves their equivalence.

problem Understanding the relationship between convex functions and p-subharmonic functions.
method Average principle, variational methods, and PDE techniques.
result Convex functions on R^n are p-subharmonic for every p > 1.

Smoothly bounded domains have special functions that are plurisubharmonic.

problem Finding smooth functions that are plurisubharmonic on bounded domains.
method Proving existence of smooth defining functions that are pp-plurisubharmonic.
result Smooth domains with smooth pp-convex boundaries admit smooth defining functions that are pp-plurisubharmonic.

We construct for every finite-dimensional Alexandrov space AA and every point pAp \in A a 22-convex function fpf_p in a small neighborhood around pp, which approximates distp2\operatorname{dist}_p^2 up to second order. Moreover, the function fpf_p can be lifted to Gromov-Hausdorff close Alexandrov spaces of the same dim…

2019-10-01abs ↗pdf ↗

We prove that the moduli space of 2-convex embedded n-spheres in R^{n+1} is path-connected for every n. Our proof uses mean curvature flow with surgery and can be seen as an extrinsic analog to Marques' influential proof of the path-connectedness of the moduli space of positive scalar curvature metics on three-manifold…

2016-07-19abs ↗pdf ↗

We supply a proof of the fact that a hyperbolic 3-manifold MM with finitely generated fundamental group and with no parabolics is topologically tame. This proves the Marden's conjecture. Our approach is to form an exhaustion MiM_i of MM and modify the boundary to make them 2-convex. We use the induced path-metric, wh…

2004-10-18abs ↗pdf ↗

An affine manifold is a manifold with torsion-free flat affine connection. A geometric topologist's definition of an affine manifold is a manifold with an atlas of charts to the affine space with affine transition functions; a radiant affine manifold is an affine manifold with holonomy consisting of affine transformati…

1997-12-19abs ↗pdf ↗

In this article, we extend the mean curvature flow with surgery to mean convex hypersurfaces with entropy less than Λn2Λ_{n-2}. In particular, 2-convexity is not assumed. Next we show the surgery flow with just the initial convexity assumption Hx,ν2>0H - \frac{\langle x, ν\rangle}{2} > 0 is possible and as an application we …

2018-04-11abs ↗pdf ↗

Using PL-methods, we prove the Marden's conjecture that a hyperbolic 3-manifold MM with finitely generated fundamental group and with no parabolics are topologically tame. Our approach is to form an exhaustion MiM_i of MM and modify the boundary to make them 2-convex. We use the induced path-metric, which makes the s…

2006-02-23abs ↗pdf ↗

We give a bound on the extinction time for a compact, strictly convex hypersurface in R^{n+1} evolving by a geometric flow where the velocity is given in terms of the curvature. This result generalizes a theorem of Colding and Minicozzi for mean curvature flow solutions to a wider class of flows studied by Ben Andrews.…

2008-05-07abs ↗pdf ↗

The paper solves a conjecture about spacelike hypersurfaces in de Sitter space.

problem Proving an Alexandrov-Fenchel inequality for closed 2-convex spacelike hypersurfaces in de Sitter space.
method Investigating the locally constrained inverse curvature flow to establish the inequality.
result Established an Alexandrov-Fenchel inequality for closed 2-convex spacelike hypersurfaces in de Sitter space.

Constructs a mean curvature flow with surgery for compact mean convex hypersurfaces.

problem Mean curvature flow with surgery for compact mean convex hypersurfaces.
method Topological surgeries performed by the flow itself through nondegenerate cylindrical singularities, adjusted at smooth times.
result Extends previous results for 2-convex flows and constructs a flow for compact mean convex hypersurfaces.

A (flat) affine 33-manifold is a 33-manifold with an atlas of charts to an affine space R3\mathbb{R}^3 with transition maps in the affine transformation group Aff(R3)\mathrm{Aff}(\mathbb{R}^3). We will show that a connected closed affine 33-manifold is either an affine Hopf 33-manifold or decomposes canonically to conca…

2014-11-05abs ↗pdf ↗

An (flat) affine 33-manifold is a 33-manifold with an atlas of charts to an affine space R3{\mathbf R}^3 with transition maps in the affine transformation group Aff(R3)Aff({\mathbf R}^3). Equivalently an affine 33-manifold is a 33-manifold with a flat torsion-free affine connection. We show that a closed affine 33-mani…

2014-07-16abs ↗pdf ↗

Two-stage nonconvex algorithm and convex relaxation both achieve optimal accuracy in noisy blind deconvolution.

problem Solving bilinear systems of equations with random noise under different designs.
method Two-stage nonconvex algorithm and convex relaxation.
result Both methods achieve minimax-optimal accuracy in the presence of random noise.

In this paper we are dealing with mean curvature flow with surgeries of two-convex hypersurfaces. The main focus is to expand on the discussion in Section 33 of Mean Curvature Flow with Surgeries of Two-Convex Hypersurfaces by Huisken and Sinestrari. Firstly we wish to establish how the neck detection lemma allows us …

2017-06-09abs ↗pdf ↗

New method glues Scherk surfaces into minimal surfaces, limiting possible outcomes.

problem Limiting the outcomes of gluing Scherk surfaces into minimal surfaces.
method Constructing minimal surfaces by stacking and gluing doubly periodic Scherk surfaces.
result Except for special cases, gluing more Scherk surfaces results in known minimal surfaces.

Study on focal surfaces of lightcone framed surfaces in Lorentz-Minkowski 3-space.

problem Investigate differential geometry properties of focal surfaces of lightcone framed surfaces.
method Introduced lightcone frame to define lightcone framed surfaces, then investigated their differential geometry properties.
result Investigated differential geometry properties of focal surfaces of lightcone framed surfaces.

Introduces hyperbolic generalized framed surfaces and their properties.

problem None explicitly stated; focuses on introducing new geometric objects.
method Generalization of hyperbolic framed surfaces and curves.
result Established conditions for a surface to be a hyperbolic generalized framed base surface and explored their singularities.

The paper studies knitted surfaces and surface-links, showing their isotopy and closure properties.

problem Understanding the isotopy and closure properties of knitted surfaces and surface-links.
method Analyzing the structure and closure of knitted surfaces and surface-links in R4\mathbb{R}^4.
result Any surface-link is ambient isotopic to the closure of a 2-dimensional knit.

Unstable minimal surfaces in n-space link to hyperbolic products.

problem Characterizing unstable minimal surfaces in Rn\mathbb{R}^n and their product counterparts.
method Lifting to R\mathbb{R}-trees, deforming to hyperbolic products, and proving instability equivalence.
result Unstable minimal surfaces in Rn\mathbb{R}^n imply unstable surfaces in product hyperbolic spaces.

Automorphisms of fine curve graphs match surface homeomorphisms for planar surfaces.

problem Understanding automorphisms of fine curve graphs on surfaces.
method Analyzing vertices and edges of fine curve graphs to match with surface homeomorphisms.
result Automorphism group of fine curve graphs is naturally isomorphic to the homeomorphism group of boundaryless planar surfaces with at least 7 punctures.

This paper connects Laguerre minimal surfaces to Weierstrass representations.

problem Understanding the relationship between Laguerre minimal surfaces and Weierstrass representations.
method Defining spherical mean curvature and providing Weierstrass-type representations for two classes of surfaces.
result Laguerre minimal surfaces are related to H2H_2-surfaces, providing a new Weierstrass-type representation.

Study on singular points of translation surfaces under linearly dependent conditions.

problem Investigate singular points of translation surfaces under linearly dependent conditions.
method Use theories of generalised framed surfaces and framed surfaces.
result Introduce translation generalised framed surfaces and investigate their singular points.