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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.

169,051 papers · 148 categories

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2515017521,002 · Jun 202019922001200920182026
48 results for critical level sets

The paper characterizes potential functions whose level sets are orbits in mechanical systems.

problem Characterizing smooth potential energy functions on the plane with specific level set properties.
method Analyzing inverse curvature flow and properties of level sets.
result Analytic or functions with totally path-disconnected critical sets must be radial, while every compact convex set is a critical set of a Levi potential.

Characterizes level-set families of harmonic functions without critical points.

problem Understanding level-set families of harmonic functions without critical points.
method Characterization via local differential-geometric condition and construction from geometric data.
result Evolution of gradient of harmonic functions determined by mean curvature of level sets.

The paper examines how the topology of level sets changes with critical points in Morse theory.

problem Understanding how the topology of level sets changes with critical points in Morse theory.
method Study of sublevel sets and level sets of Morse functions, analysis of critical points and their indices.
result For a general class of functions, the topology of a regular level set changes when passing a single critical point, unless the index is half the dimension of the manifold.

Analyzes properties of transnormal Finsler functions on compact manifolds.

problem Properties of transnormal Finsler functions on compact manifolds.
method Analyzes critical level sets and partition properties of transnormal functions.
result Critical level sets of an analytic transnormal function are submanifolds, and the partition of MM into level sets is a Finsler partition.

We prove that the level sets of a real C^s function of two variables near a non-degenerate critical point are of class C^[s/2] and apply this to the study of planar sections of surfaces close to the singular section by the tangent plane at hyperbolic points or elliptic points, and in particular at umbilic points. We al…

2005-04-19abs ↗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.

Study of symmetries of sphere divisions induced by functions with isolated critical points.

problem Understanding symmetries of sphere divisions induced by functions with isolated critical points.
method Analyzing the group of diffeomorphisms that leave invariant a connected component of a level set and its complement.
result The group of such diffeomorphisms is isomorphic to a finite subgroup of SO(3)SO(3).

Researchers compute trace formula for magnetic Laplacian on hyperbolic surfaces.

problem Analyzing the magnetic Laplacian on compact hyperbolic surfaces.
method Computed the trace formula for magnetic Laplacian energies above the Mane critical level.
result Asymptotic behavior of trace formula coefficients near the Mane critical level.

The paper explores the structure of Reeb spaces for smooth functions on manifolds.

problem Understanding the structure of Reeb spaces for smooth functions on manifolds.
method Proving the structure of Reeb spaces and showing that any graph can be realized as a Reeb space.
result The Reeb space of a smooth function on a closed manifold with finitely many critical values has a graph structure.

Model criticism tool evaluates text coherence and structure in generated long-form text.

problem Evaluate the high-level structure of generated text for coherence, coreference, and topicality.
method Apply model criticism in latent space to compare real and generated data distributions.
result Transformer-based models struggle with maintaining structural coherence and coreference.

New Morse-Bott function defined on Stiefel manifolds, revealing complex critical structures.

problem Defining Morse-Bott functions on non-linear Stiefel manifolds.
method Replacing linear height function with a quadratic one, proving it as a Morse-Bott function.
result Critical submanifolds are fibrations of products of Grassmannians, not Grassmannians themselves.

Single-timescale actor-critic finds globally optimal policy.

problem Finding globally optimal policy in reinforcement learning.
method Simultaneous actor and critic updates with linear or deep neural network approximations.
result Actor sequence converges to globally optimal policy at O(K1/2)O(K^{-1/2}) rate.

We prove that the number of critical points of a Li-Tam Green's function on a complete open Riemannian surface of finite type admits a topological upper bound, given by the first Betti number of the surface. In higher dimensions, we show that there are no topological upper bounds on the number of critical points by con…

2010-05-28abs ↗pdf ↗

A methodology is developed to identify, as units of study, each decrease in the value of a stock from a given maximum price level. A critical level in the amount of price declines is found to separate a segment operating under a random walk from a segment operating under a power law. This level is interpreted as a poin…

2016-04-13abs ↗pdf ↗

Given a smooth closed oriented manifold MM of dimension nn embedded in Rn+2\mathbb{R}^{n+2} we study properties of the `solid angle' function Φ ⁣:Rn+2MS1Φ\colon\mathbb{R}^{n+2}\setminus M\to S^1. It turns out that a non-critical level set of ΦΦ is an explicit Seifert hypersurface for MM.

2017-06-20abs ↗pdf ↗

Multilayer graphs are commonly used for representing different relations between entities and handling heterogeneous data processing tasks. New challenges arise in multilayer graph clustering for assigning clusters to a common multilayer node set and for combining information from each layer. This paper presents a theo…

2016-09-23abs ↗pdf ↗

The paper finds infinitely many magnetic geodesics on non-compact manifolds.

problem Existence and multiplicity of periodic orbits of magnetic flows.
method Morse theory applied to non-compact manifolds with energy levels above the Mañé critical value.
result Infinitely many noncontractible closed magnetic geodesics found.

Study estimates personalized effects of maternal PM2.5 exposure on birth weight.

problem Identify critical windows and heterogeneity in maternal PM2.5 exposure effects on birth weight.
method Heterogeneous Distributed Lag Models and Bayesian Additive Regression Trees.
result Evidence of heterogeneity in PM2.5-birth weight relationship, with some dyads showing 3x larger decrease.

The monodromy action in the homology of level sets of Morse functions on stratified singular analytic varieties is studied. The local variation operators in both the standard and the intersection homology groups defined by the loops around the critical values of such functions are reduced to similar operators in the ho…

1995-05-11abs ↗pdf ↗

The paper studies conditions for graphs connecting level sets of harmonic polynomials.

problem Conditions for graphs connecting level sets of harmonic polynomials.
method Algebraic properties and Kempf-Ness functional construction.
result Stability condition equivalent to the existence of a solution to the deformed Hermitian-Yang-Mills equation.

For a monotonically advancing front, the arrival time is the time when the front reaches a given point. We show that it is twice differentiable everywhere with uniformly bounded second derivative. It is smooth away from the critical points where the equation is degenerate. We also show that the critical set has finite …

2015-01-30abs ↗pdf ↗

New proofs of Cheeger-like inequalities for coexact 1-forms on hyperbolic manifolds.

problem Cheeger-like inequalities for coexact 1-forms on hyperbolic manifolds.
method Properties of magnetic geodesic flow and behavior at Mañé's critical energy level.
result Improved Cheeger constants and volume dependence in proofs.

We study the asymptotic behaviour of 1-parameter subgroups with respect to Hofer's metric when the underlying symplectic manifold is an open surface of infinite area. We prove that, depending on the topology of the level sets of the Hamiltonian H, the distance either is bounded or behaves asymptotically linear. Moreove…

1999-05-10abs ↗pdf ↗

This paper was motivated by work of Arnold where he explains how to count "snakes", i.e. Morse functions on the real axis with prescribed behavior at infinity. This leads immediately to a count of excellent Morse functions on the circle, where following Thom's terminology, excellent means that no two critical points li…

2005-12-21abs ↗pdf ↗

Paper proposes PRR network for better experience reuse in reinforcement learning.

problem Efficient experience reuse in reinforcement learning across multiple granularities.
method Proposes PRR network trained on multi-level architecture to extract and store experience.
result PRR network leads to better experience reuse and improved performance.

We investigate the Dolbeault operator on a pair of pants, i.e., an elementary cobordism between a circle and the disjoint union of two circles. This operator induces a canonical selfadjoint Dirac operator DtD_t on each regular level set CtC_t of a fixed Morse function defining this cobordism. We show that as we approac…

2009-08-24abs ↗pdf ↗

New study proves no strictly positive solutions to a specific Laplace equation on certain manifolds.

problem Existence of strictly positive solutions to a critical Laplace equation on manifolds with nonnegative Ricci curvature.
method Analyzed a suitable function defined along the level sets of the solution.
result No strictly positive solutions exist unless the manifold is isometric to R^n and the solution is a Talenti function.

Let XX be a simplicial complex with a piecewise linear function f:XRf:X\to\mathbb{R}. The Reeb graph Reeb(f,X)Reeb(f,X) is the quotient of XX, where we collapse each connected component of f1(t)f^{-1}(t) to a single point. Let the nodes of Reeb(f,X)Reeb(f,X) be all homologically critical points where any homology of the corresponding c…

2013-12-05abs ↗pdf ↗

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.