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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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157313470626 · Jun 202019922001200920172026
48 results for connected mean convex regions

The paper proves a theorem about mean curvature in Euclidean and hyperbolic spaces.

problem Proving a theorem about mean curvature in Euclidean and hyperbolic spaces.
method Analyzing connected mean convex regions with at least two components in Rn+1\mathbb{R}^{n+1} and hyperbolic space.
result Connected mean convex regions in Rn+1\mathbb{R}^{n+1} with at least two components cannot have strictly positive mean curvature.

Consider the mean curvature flow of an (n+1)-dimensional, compact, mean convex region in Euclidean space (or, if n<7, in a Riemannian manifold). We prove that elements of the m-th homotopy group of the complementary region can die only if there is a shrinking S^k x R^(n-k) singularity for some k less than or equal to m…

2011-07-23abs ↗pdf ↗

In this short article we investigate the topology of the moduli space of two-convex embedded tori Sn1×S1Rn+1S^{n-1}\times S^1\subset \mathbb{R}^{n+1}. We prove that for n3n \geq 3 this moduli space is path-connected, and that for n=2n = 2 the connected components of the moduli space are in bijective correspondence with the knot…

2017-03-06abs ↗pdf ↗

We prove that every plane passing through the origin divides an embedded compact free boundary minimal surface of the euclidean 33-ball in exactly two connected surfaces. We also show that if a region in the ball has mean convex boundary and contains a nullhomologous diameter, then this region is a closed halfball. Mo…

2019-07-09abs ↗pdf ↗

The study proves the existence of free boundary minimal disks in convex regions.

problem Proving the existence of free boundary minimal disks in convex regions.
method Based on a multiplicity-one theorem for the free boundary Simon-Smith min-max theory.
result Existence of at least three embedded free boundary minimal disks in strictly convex domains with nonnegative Ricci curvature.

Region-specific linear models are widely used in practical applications because of their non-linear but highly interpretable model representations. One of the key challenges in their use is non-convexity in simultaneous optimization of regions and region-specific models. This paper proposes novel convex region-specific…

2014-10-31abs ↗pdf ↗

We prove that for the mean curvature flow of two-convex hypersurfaces the intrinsic diameter stays uniformly controlled as one approaches the first singular time. We also derive sharp Ln1L^{n-1}-estimates for the regularity scale of the level set flow with two-convex initial data. Our proof relies on a detailed analysis…

2017-10-27abs ↗pdf ↗

The generalized soap bubble problem seeks the least perimeter way to enclose and separate n given volumes in R^m. We study the possible configurations for perimeter minimizing bubble complexes enclosing more than two regions. We prove that perimeter minimizing planar bubble complexes with equal pressure regions and wit…

1998-08-11abs ↗pdf ↗

The paper proves inequalities for star-shaped and FF-mean convex hypersurfaces in Rn+1\mathbb{R}^{n+1}.

problem Proving geometric inequalities for specific types of hypersurfaces.
method Using anisotropic pp-momentum, perimeter, and volume, the paper derives inequalities for star-shaped and FF-mean convex hypersurfaces.
result The Wulff shape of FF is the unique minimizer of the corresponding functionals among all star-shaped and FF-mean convex sets.

We prove, in all dimensions n2n\geq 2, that there exists a convex translator lying in a slab of width πsecθπ\secθ in Rn+1\mathbb{R}^{n+1} (and in no smaller slab) if and only if θ[0,π2]θ\in[0,\fracπ{2}]. We also obtain convexity and regularity results for translators which admit appropriate symmetries and study the asymptotics a…

2018-05-14abs ↗pdf ↗

Uniform spectral gap for convex cocompact hyperbolic surfaces and expanders.

problem Spectral gap for convex cocompact hyperbolic surfaces and their covers.
method Using thermodynamic formalism for twisted Selberg zeta functions.
result Uniform resonance-free regions for convex cocompact hyperbolic surfaces and expanders.

We consider compact convex hypersurfaces contracting by functions of their curvature. Under the mean curvature flow, uniformly convex smooth initial hypersurfaces evolve to remain smooth and uniformly convex, and contract to points after finite time. The same holds if the initial data is only weakly convex or non-smoot…

2011-04-05abs ↗pdf ↗

Under mean curvature flow, a closed, embedded hypersurface M(t)M(t) becomes singular in finite time. For certain classes of mean-convex mean curvature flows, we show the continuity of the first singular time TT and the limit set "M(T)M(T)", with respect to initial data. We employ an Angenent-like neck-pinching argument to…

2017-03-07abs ↗pdf ↗

In the last 15 years, White and Huisken-Sinestrari developed a far-reaching structure theory for the mean curvature flow of mean convex hypersurfaces. Their papers provide a package of estimates and structural results that yield a precise description of singularities and of high curvature regions in a mean convex flow.…

2013-04-03abs ↗pdf ↗

We show that for neural network functions that have width less or equal to the input dimension all connected components of decision regions are unbounded. The result holds for continuous and strictly monotonic activation functions as well as for the ReLU activation function. This complements recent results on approxima…

2018-07-03abs ↗pdf ↗

We consider the problem of minimizing the relative perimeter under a volume constraint in an unbounded convex body CRn+1C\subset \mathbb{R}^{n+1}, without assuming any further regularity on the boundary of CC. Motivated by an example of an unbounded convex body with null isoperimetric profile, we introduce the concept of…

2016-06-13abs ↗pdf ↗

The paper studies hypersurfaces in spheres using mean curvature flow with surgery.

problem Studying hypersurfaces in spheres under specific curvature pinching conditions.
method Using mean curvature flow with surgery to preserve and analyze curvature pinching conditions.
result Hypersurfaces satisfying the pinching condition are diffeomorphic to spheres or connected sums of spheres.

This work analyzes a two-stage algorithm for single index models, showing precise asymptotics of gradient descent.

problem Learning single index models with non-convex optimization.
method Spectral initialization followed by gradient descent, with detailed analysis of dynamics and asymptotics.
result Gradient descent converges to long-time fixed points in the large system limit, representing mean field behavior.

Paper reconstructs compact Riemannian manifolds from travel time data.

problem Reconstructing compact Riemannian manifolds from partial travel time data.
method Embedding in function space, studying distance function regularity.
result Reconstruction of compact Riemannian manifolds from travel time data.

The renormalized volume is reinterpreted using isoperimetric profiles.

problem Understanding the renormalized volume of convex co-compact hyperbolic 3-manifolds.
method Using isoperimetric profiles and Minkowski inequalities.
result A sharp Minkowski inequality for horospherically convex sets in H3\mathbb{H}^3.

The paper proves inequalities for closed surfaces involving mean curvature.

problem Proving geometric inequalities for closed surfaces in Euclidean space.
method Verification of inequalities for convex surfaces and addressing Topping's conjecture.
result Optimal scaling law between Willmore energy and isoperimetric ratio for convex surfaces.

The paper extends Liebmann's Theorem to convex hypersurfaces with boundary.

problem Proving properties of convex hypersurfaces with boundary in Euclidean space.
method Analyzing locally convex, embedded, compact, connected CMC hypersurfaces bounded by a closed strictly convex submanifold.
result Spherical caps are the only such hypersurfaces with non-zero constant mean curvature bounded by a (n1)(n-1)-sphere.

PULSE estimator improves prediction in causal inference with bounded interventions.

problem Optimizing causal models for bounded interventions.
method Relates K-class estimators to anchor regression, introduces PULSE estimator for minimization of mean squared prediction error with bounded constraints.
result PULSE estimator outperforms other estimators in real data and simulation experiments, especially in weak instrument settings.

The Levi-Civita connection and geodesic equations for a stationary spacetime are studied in depth. General formulae which generalize those for warped products are obtained. These results are applicated to some regions of Kerr spacetime previously studied by using variational methods. We show that they are neither space…

2001-06-20abs ↗pdf ↗

Develops a method to prove Penrose inequality for half-spaces.

problem Proving the Riemannian Penrose inequality for asymptotically flat half-spaces.
method Doubling procedure for asymptotically flat half-spaces with non-negative scalar curvature and mean-convex boundary.
result Obtains the Penrose-type inequality for dimensions 3 to 7.

Study shows bound on Uryson width for specific 3D manifolds.

problem Bounding Uryson width for 3D manifolds with non-negative Ricci curvature and strictly mean convex boundary.
method Proved existence of a Morse function with uniform diameter bounds on level sets.
result Upper bound on Uryson width for the specified 3D manifolds.

Study geodesic X-ray transform and streaking artifacts on simple surfaces or spaces of constant curvature.

problem Streaking artifacts in CT images due to metal regions.
method Geodesic X-ray transform on nontrapping compact Riemannian manifolds with strictly convex boundaries.
result Streaking artifacts result from conormal singularities along common tangent geodesics.

The paper analyzes how SGD visits different regions of a non-convex problem's state space.

problem Understanding the long-run distribution of stochastic gradient descent in non-convex problems.
method Large deviations theory and randomly perturbed dynamical systems.
result The long-run distribution of SGD resembles the Boltzmann-Gibbs distribution with temperature equal to the step-size.

We completely characterize isoperimetric regions in R^n with density e^h, where h is convex, smooth, and radially symmetric. In particular, balls around the origin constitute isoperimetric regions of any given volume, proving the Log-Convex Density Conjecture due to Kenneth Brakke.

2013-11-16abs ↗pdf ↗

Study high codimension mean curvature flow in Riemannian manifolds, proving limiting flow in Euclidean space.

problem Analyzing mean curvature flow in high codimension Riemannian manifolds.
method Establishing codimension estimate, using quadratic pinching condition, gradient estimates.
result Existence of limiting flow in Euclidean space under cylindrical pinching condition.