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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.

168,657 papers · 148 categories

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135269404538 · Jun 202019922001200920172026
48 results for stable/unstable spaces

The Ricci flow on the 2-sphere with marked points is shown to converge in all three stable, semi-stable, and unstable cases. In the stable case, the flow was known to converge without any reparametrization, and a new proof of this fact is given. The semi-stable and unstable cases are new, and it is shown that the flow …

2014-07-04abs ↗pdf ↗

SFB uses stable features to adapt unstable ones for better performance.

problem Improving classifier performance on out-of-distribution data by leveraging stable features.
method SFB learns a predictor that separates stable and unstable features, then adapts unstable predictions using stable predictions.
result SFB can learn an asymptotically-optimal predictor without test-domain labels.

This paper describes the construction of a canonical compactification of the space of trajectories and of the unstable/stable sets of a generic gradient like vector field on a closed manifold as well as a canonical structure of a smooth manifold with corners of these spaces. As an application we discuss the geometric c…

2011-01-04abs ↗pdf ↗

New proof associates partitions to isotopic pseudo-Anosov homeomorphisms.

problem Stable and unstable foliations for pseudo-Anosov homeomorphisms.
method Geometric realization of Fathi's result for isotopic homeomorphisms.
result Associated stable and unstable partitions for isotopic pseudo-Anosov homeomorphisms.

New minimal 2-spheres found in hyperkähler 4-manifolds, unstable and not holomorphic.

problem Characterizing stable minimal surfaces in hyperkähler 4-manifolds.
method Gluing construction using Scherk and Taub-NUT surfaces, harmonic map parametrization.
result Existence of unstable minimal 2-spheres with degree-1 Gauss lift, not holomorphic.

Algorithm identifies and transfers unstable features to create robust classifiers.

problem Developing unbiased classifiers from input-label pairs alone.
method Contrast different data environments in source tasks to encode unstable features, then cluster target task data and minimize worst-case risk.
result Our method maintains robustness across synthetic and real-world environments.

Study hermitian Yang-Mills connections on pullback bundles for holomorphic submersions.

problem Investigate hermitian Yang-Mills connections on pullback bundles for holomorphic submersions.
method Obtain a criterion for the existence of hermitian Yang-Mills connections on pullback bundles, using intersection numbers on the base.
result Determine conditions under which pullback bundles of stable or unstable bundles remain stable or unstable for adiabatic classes.

CV inference can be invalid for relatively unstable model comparisons.

problem The validity of cross-validation for model comparison is questioned when models are relatively unstable.
method The study proves that simple, individually stable models can generate relatively unstable comparisons, invalidating CV inference.
result The Lasso and soft-thresholding generate relatively unstable comparisons, invalidating CV inferences.

Anosov diffeomorphisms with integrable subbundles have coherent dynamics and spectral rigidity.

problem Characterizing Anosov diffeomorphisms with integrable subbundles.
method Joint integrability of strong stable and unstable subbundles leads to coherent dynamics and spectral rigidity.
result Anosov diffeomorphisms with integrable subbundles are dynamically coherent and have spectral rigidity.

We investigate various structures associated with the hyperbolic Markov and homological spectra of a pseudoAnosov map φφ on a surface. Each unstable eigenvalue of the action of φφ on first cohomolgy yields an eigen-cocycle that is transverse and holonomy invariant to the stable foliation Fs\mathcal{F}^s of φφ. Each …

2010-09-15abs ↗pdf ↗

In this paper we describe the stable and unstable leaves for the geodesic flow on the space of non-wandering spacelike geodesics of a Margulis Space Time and prove contraction properties of the leaves under the flow. We also show that monodromy of Margulis Space Times are "Anosov representations in non semi-simple Lie …

2014-12-28abs ↗pdf ↗

Math proves deep learning unstable, despite stable neural networks existing.

problem Unstable neural networks in deep learning despite stable ones existing.
method Mathematical proof showing instability of current training procedures.
result Proven existence of stable and accurate neural networks with variable dimensions, but current algorithms cannot compute them.

We prove a general homological stability theorem for certain families of groups equipped with product maps, followed by two theorems of a new kind that give information about the last two homology groups outside the stable range. (These last two unstable groups are the "edge" in our title.) Applying our results to auto…

2016-08-31abs ↗pdf ↗

Study develops electronic phenotypes of ICU patient acuity.

problem Limited time for patient acuity assessments and imprecise clinical trajectory prediction.
method Developed electronic phenotypes using automated variable retrieval in electronic health records.
result Identified three phenotypes: persistently stable, persistently unstable, and transitioning from unstable to stable.

In this paper, we study the stability of catenoids and helicoids in the hyperbolic 33-space H3\mathbb{H}^3. (1) For a family of spherical minimal catenoids {Ca}a>0\{\mathcal{C}_a\}_{a>0} in H3\mathbb{H}^3, there exist two constants 0<ac<al0<a_c<a_l such that \bullet Ca\mathcal{C}_a is an unstable minimal surface with index o…

2016-08-06abs ↗pdf ↗

Riemannian manifolds with non-zero Killing spinors are Einstein manifolds. Klaus Kröncke proved that all complete Riemannian manifolds with imaginary Killing spinors are (linearly) strictly stable in \cite{Kro15}. In this paper, we obtain a new proof for this stability result by using a Bochner type formula in \cite{DW…

2016-05-23abs ↗pdf ↗

In this article, we thoroughly investigate the stability inequality for Ricci-flat cones. Perhaps most importantly, we prove that the Ricci-flat cone over CP^2 is stable, showing that the first stable non-flat Ricci-flat cone occurs in the smallest possible dimension. On the other hand, we prove that many other example…

2011-11-21abs ↗pdf ↗

Study shows configuration spaces' homological dimension increases monotonically.

problem Understanding the homological properties of configuration spaces of manifolds.
method Analyzing the homological monotonicity of unordered configuration spaces of manifolds.
result Homological dimension of configuration spaces increases monotonically in each degree.

Study of embedding spaces using homotopy theory and operads.

problem Understanding the stable homotopy type of embedding spaces.
method Analysis of cubes of framed configuration spaces, homotopy theory of presheaves, operadic structures.
result Induced action of the Poisson operad on the homology of configuration spaces is a homotopy invariant.

In this paper, we investigate the Hamiltonian-stability of Lagrangian tori in the complex hyperbolic space CHn\mathbb{C}H^n. We consider a standard Hamiltonian TnT^n-action on CHn\mathbb{C}H^n, and show that every Lagrangian TnT^n-orbits in CHn\mathbb{C}H^n is H-stable when n2n\leq 2 and there exist infinitely many H-unst…

2018-08-23abs ↗pdf ↗

This article deals with stability issues related to geodesic X-ray transforms, where an interplay between the (attenuation type) weight in the transform and the underlying geometry strongly impact whether the problem is stable or unstable. In the unstable case, we also explain what types of artifacts are expected in te…

2017-08-29abs ↗pdf ↗

In case of the heat flow on the free loop space of a closed Riemannian manifold non-triviality of Morse homology for semi-flows is established by constructing a natural isomorphism to singular homology of the loop space. The construction is also new in finite dimensions. The main idea is to build a Morse filtration usi…

2014-08-17abs ↗pdf ↗

This work examines the stability of GD and SGD near minima, revealing nonlinear dynamics that differ from linear analysis.

problem The stability of optimization algorithms like GD and SGD near minima is not well understood.
method The authors derive an exact criterion for stable oscillations of GD near minima in the multivariate setting, considering high-order derivatives.
result Nonlinear dynamics can diverge in expectation even if a single batch is unstable, challenging linear analysis.

In our previous work [PSSW], we showed that the Ricci flow on S^2 whose initial metric has conical singularities \sum_{j=1}^k β_j[p_j] converges to a constant curvature metric with conic singularities (in the stable and semi-stable cases) or to a gradient shrinking soliton with conical singularities (in the unstable ca…

2015-03-15abs ↗pdf ↗

Stable health predictions need deconfounding test set features.

problem Stability of predictions in health machine learning is compromised by selection biases.
method Deconfounding the test set features improves prediction stability across different environments.
result Improved stability achieved by deconfounding test set features.

For a family of spherical minimal catenoids C_a in the hyperbolic 3-space, there exist two constants 0<a_c<a_l such that the following are true: (1) C_a is an unstable minimal surface with index one if a<a_c, (2) C_a is a stable minimal surface if a>=a_c, and (3) C_a is a least area minimal surface in the sense of Meek…

2012-04-22abs ↗pdf ↗

Establishes bounds on Andrews-Curtis moves for trivial group presentations.

problem Understanding presentations of the trivial group and Andrews-Curtis moves.
method Explicit upper bounds on stable Andrews-Curtis moves for thickenable presentations.
result Thickenable presentations of the trivial group satisfy the Andrews-Curtis conjecture.

Real analytic maps can be unstable even if infinitesimal changes are stable.

problem Unstability of real analytic maps despite infinitesimal stability.
method Used a relative version of Whitney's Analytic Approximation Theorem and H. Cartan's Theorems A and B.
result Infinitesimal CωC^{\omega} stability does not imply CωC^{\omega} stability.

In this article, we systematically investigate the stability properties of certain warped product Einstein manifolds. We characterize stability of these metrics in terms of an eigenvalue condition of the Einstein operator on the base manifold. In particular, we prove that all complete manifolds carrying imaginary Killi…

2015-07-07abs ↗pdf ↗

Proposes a stable classifier using inflated argmax for multiclass classification.

problem Inherent instability of taking the maximizer in multiclass classification.
method Bagging for stable continuous scores, inflated argmax for stable labels.
result Inflated argmax provides necessary protection against unstable classifiers without loss of accuracy.

A novel framework interprets driving patterns using Action phases clustering.

problem Challenges in comprehending driving heterogeneity from underlying behavior mechanisms.
method Resampling and Downsampling Method (RDM) followed by iterative clustering calibration.
result Six driving patterns identified in real-world datasets, revealing dynamic nature of driving.

Study shows instability of Kähler Ricci solitons and stability of orbifold singularities.

problem Linear stability and instability of Kähler Ricci solitons.
method Extending the approach of \cite{chi04} and \cite{hm11}, via recent work \cite{cm21} on gradient shrinking Ricci solitons.
result Linear instability of the BCCD shrinking soliton and stability of orbifold singularities of Kähler solitons.

The study examines stability of fibres on Hopf surfaces as harmonic maps and minimal surfaces.

problem Stability of fibres on Hopf surfaces as harmonic maps and minimal surfaces.
method Construction of Hermitian metrics on Hopf surface and analysis of fibres as harmonic maps and minimal surfaces.
result Two toric fibres are stable minimal surfaces, while others are unstable.