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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.

169,181 papers · 148 categories

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48 results for Markov spectrum

Proves simplicity of Lyapunov exponents for specific Anosov flows.

problem Proving all Lyapunov exponents have multiplicity 1 for certain Anosov flows.
method Perturbative results for flows, modification of eigenvalues, Markov partition, and simplicity criterion.
result In a C1C^1-open and CkC^k-dense set of Anosov flows, all Lyapunov exponents have multiplicity 1.

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 ↗

VAE improves MCMC efficiency by generating diverse prior proposals.

problem Inefficient MCMC methods in Bayesian inverse problems, especially subsurface flow modeling.
method Uses Variational Autoencoder (VAE) to generate broader-spectrum prior proposals.
result VAE achieves comparable accuracy to Karhunen-Loève Expansion (KLE) and outperforms it when correlation length is unknown.

We prove a lower bound for the kk-th Steklov eigenvalues in terms of an isoperimetric constant called the kk-th Cheeger-Steklov constant in three different situations: finite spaces, measurable spaces, and Riemannian manifolds. These lower bounds can be considered as higher order Cheeger type inequalities for the Ste…

2017-05-24abs ↗pdf ↗

Paper proposes efficient inference for hidden Markov models with memory decay.

problem Challenges in scalability due to dependencies in hidden Markov model observation data.
method Utilizes memory decay to carry out forward and backward probabilities with subsequences, enabling efficient inference over long sequences.
result Developed an efficient algorithm to numerically estimate the gap of top Lyapunov exponents, which determines the length of subsequences.

Adaptive Bayesian model for covariate-dependent power spectra analysis.

problem Estimating complex relationships and interactions between covariates and power spectra.
method Bayesian sum of trees model with local power spectrum estimation and reversible-jump MCMC for tree modifications.
result The method can accurately recover both smooth and abrupt changes in power spectra across multiple covariates.

Free Random Projection enhances reinforcement learning by naturally incorporating hierarchical structure.

problem Improving reinforcement learning algorithms for better generalization and adaptability.
method Introduces Free Random Projection, a method that uses free probability theory to create random orthogonal matrices encoding hierarchical structure.
result Empirically shows consistent improvement in generalization over standard methods on multi-environment benchmarks.

We define a new spectrum for compact length spaces and Riemannian manifolds called the "covering spectrum" which roughly measures the size of the one dimensional holes in the space. More specifically, the covering spectrum is a set of real numbers δ>0δ>0 which identify the distinct δδ covers of the space. We investigat…

2003-11-22abs ↗pdf ↗

Study the energy spectrum of metrics on surfaces and its relation to simple length spectrum.

problem Relate the energy spectrum to the simple length spectrum of metrics on surfaces.
method Analyze the energy spectrum of metrics on surfaces and their Teichmüller spaces, considering homotopy conditions.
result The energy spectrum determines the simple length spectrum under certain conditions.

The paper compares two spectrum definitions and finds stability in one modification.

problem Generalizing eigenvalues to arbitrary functionals with stability.
method Comparison of Gromov's homotopy significant spectrum and Krasnoskii spectrum, with a modified definition of the homotopy significant spectrum.
result The modified homotopy significant spectrum is stable, and Cheeger constant corresponds to Krasnoskii eigenvalue.

Develops a new spectrum for annular links, recovering a transverse invariant at extreme gradings.

problem Understanding transverse link invariants in the annular setting.
method Constructs a stable homotopy type for annular links and defines a map to the Khovanov skein spectrum.
result At extreme gradings, the map from the Khovanov spectrum to the Khovanov skein spectrum recovers the cohomotopy transverse invariant.

Constructs manifolds with specific spectral properties.

problem Spectral properties of Riemannian manifolds.
method Asymptotically hyperbolic manifolds with sharp curvature bounds.
result Embeds singular continuous spectrum into the essential spectrum of the Laplacian.

The spectrum of certain manifolds matches that of hyperbolic space if the bottom spectrum is maximal.

problem Investigating spectral rigidity of manifolds with Ricci bounded below and maximal bottom spectrum.
method Analyzing the spectrum of the Laplacian on manifolds with specific Ricci curvature bounds.
result The spectrum of the manifold coincides with that of hyperbolic space if the bottom spectrum is maximal.

Paper presents a method to train NER models without labelled data using weak supervision.

problem Dealing with NER performance drop in new domains without labelled data.
method Weak supervision through automatic annotation and hidden Markov model integration.
result Improvement of about 7 percentage points in entity-level F1F_1 scores.

A machine learning approach for efficient spectrum sharing in distributed DSA networks.

problem Effective spectrum sharing among secondary users (SUs) and primary users (PUs) in a distributed network.
method Deep reinforcement learning (DRL) combined with reservoir computing (RC) for distributed spectrum access decisions.
result The RC-based spectrum access strategy significantly reduces collision chances and outperforms other methods.

In 2004, Sormani and Wei introduced the covering spectrum: a geometric invariant that isolates part of the length spectrum of a Riemannian manifold. In their paper they observed that certain Sunada isospectral manifolds share the same covering spectrum, thus raising the question of whether the covering spectrum is a sp…

2009-05-01abs ↗pdf ↗

Study shows ortho spectrum doesn't fully determine systolic length but limits the number of possible structures.

problem Determining the systolic length of hyperbolic surfaces with boundary.
method Analyzing the ortho spectrum of hyperbolic surfaces with totally geodesic boundary.
result There are only finitely many possibilities for the ortho spectrum and corresponding hyperbolic structures.

The rigidity of marked length spectrum for closed hyperbolic surfaces due to Fricke-Klein [7] has been the motivation of many different rigidity results, specially for manifolds of negative curvature. From the works of Vigneras [18], Sunada [17] and many other authors this result is far from being true for the unmarked…

2017-01-30abs ↗pdf ↗

ManifoldFlow relaxes fixed-spectrum Stiefel layers to learn a positive spectrum.

problem Fixed-spectrum Stiefel layers impose rigid spectral constraints.
method Introduces ManifoldFlow, a relaxation that learns a positive spectrum while keeping the basis on the Stiefel manifold.
result Learnable SPD spectrum improves performance in various settings.

Study essential spectrum of differential operators on geometrically finite orbifolds.

problem Analyzing the essential spectrum of differential operators over specific geometric structures.
method Investigates first order and Laplace type elliptic differential operators on Riemannian vector bundles over geometrically finite orbifolds.
result Discovers properties of essential spectra for these operators.

Study on length spectrum of random hyperbolic 3-manifolds.

problem Understanding the length spectrum of random hyperbolic 3-manifolds.
method Modeling random hyperbolic 3-manifolds using truncated tetrahedra and analyzing their length spectrum as volume tends to infinity.
result The length spectrum converges in distribution to a Poisson point process with a computable intensity λ as volume increases.

Paper proves flat metrics from holomorphic quadratic differentials can be identified by length spectrum.

problem Identifying flat metrics from holomorphic quadratic differentials.
method Proved using length spectrum on closed oriented surfaces.
result Flat metrics from holomorphic quadratic differentials can be distinguished by their length spectrum.

Proves existence of solutions to Poisson equation on manifolds with positive spectrum.

problem Existence of solutions to Poisson equation on manifolds with positive essential spectrum.
method Sharp pointwise decay on source function, unbounded Ricci curvature, general spectrum and curvature bounds.
result Existence of solutions on manifolds with positive essential spectrum and unbounded Ricci curvature.

The study of the spectrum of the Laplacian on forms over manifolds.

problem Analyzing the spectrum of the Laplacian on forms over manifolds with specific curvature properties.
method Generalization of Weyl's criterion, Cheeger-Fukaya-Gromov theory, and continuous perturbations of the operator.
result Significantly stronger results for the spectrum of the Laplacian on forms, including its behavior under metric deformations.