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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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77155232309 · Jun 202019922001200920172026
48 results for Critical levels

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.

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.

In this study, we investigate the use of global information to speed up the learning process and increase the cumulative rewards of reinforcement learning (RL) in competition tasks. Within the actor-critic RL, we introduce multiple cooperative critics from two levels of the hierarchy and propose a reinforcement learnin…

2019-02-08abs ↗pdf ↗

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.

We study the level sets of the distance function from a boundary point of a convex set in Euclidean space. We provide a lower bound for the range of connectivity of the level sets, in terms of the critical points of the distance function in the sense of Grove-Shiohama-Gromov-Cheeger.

2019-10-06abs ↗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 ↗

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.

Classical Morse theory proceeds by considering sublevel sets f1(,a]f^{-1}(-\infty, a] of a Morse function f:MRf: M \to R, where MM is a smooth finite-dimensional manifold. In this paper, we study the topology of the level sets f1(a)f^{-1}(a) and give conditions under which the topology of f1(a)f^{-1}(a) changes when passing a cri…

2019-10-11abs ↗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.

Families of hypersurfaces that are level-set families of harmonic functions free of critical points are characterized by a local differential-geometric condition. Harmonic functions with a specified level-set family are constructed from geometric data. As a by-product, it is shown that the evolution of the gradient of …

2018-12-05abs ↗pdf ↗

Deep neural networks (DNNs) are vulnerable to maliciously generated adversarial examples. These examples are intentionally designed by making imperceptible perturbations and often mislead a DNN into making an incorrect prediction. This phenomenon means that there is significant risk in applying DNNs to safety-critical …

2018-10-09abs ↗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.

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 ↗

In this note we discuss a few properties of transnormal Finsler functions, i.e., the natural generalization of distance functions and isoparametric Finsler functions. In particular, we prove that critical level sets of an analytic transnormal function are submanifolds, and the partition of MM into level sets is a Fins…

2018-07-23abs ↗pdf ↗

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.

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 ↗

Parastatistic distribution of a total debt owed to a large number of creditors considered in relation to the duration of these debts. The process of debt calculation depends on the fractal dimension of economic system in which this process takes place. Two actual variants of these dimensions are investigated. Critical …

2016-01-28abs ↗pdf ↗

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.

Bayesian CNN improves MRI stroke diagnosis accuracy and uncertainty quantification.

problem Uncertainty quantification in automated image analysis for medical decision-making.
method Bayesian Convolutional Neural Network (CNN) with aggregation methods for patient-level diagnoses.
result Bayesian CNN achieved 95.33% accuracy on 511 patients, 2% higher than non-Bayesian.

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 introduce a new critical value c(L)c_\infty(L) for Tonelli Lagrangians LL on the tangent bundle of the 2-sphere without minimizing measures supported on a point. We show that c(L)c_\infty(L) is strictly larger than the Mañé critical value c(L)c(L), and on every energy level e(c(L),c(L))e\in(c(L),c_\infty(L)) there exist infinitely…

2017-02-28abs ↗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.

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 ↗

For a given level of accuracy in option prices, the paper considers the problem of deciding when exactly, as one or more of the pricing parameters change, a barrier option degenerates into a simpler type of option. This problem is meaningful in the real world where option prices are always determined within a certain l…

2008-06-28abs ↗pdf ↗

Kirchhoff energy is a classical functional on the space of arclength-parameterized framed curves whose critical points approximate configurations of springy elastic rods. We introduce a generalized functional on the space of framed curves of arbitrary parameterization, which model rods with axial stretch or cross-secti…

2017-08-30abs ↗pdf ↗