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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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102203305406 · Jun 202019922001200920172026
48 results for concentration parameter

Study on Dirichlet process mixtures for clustering consistency.

problem Consistency of clustering with Dirichlet process mixtures.
method Analysis of posterior distribution as sample size increases, focusing on consistency for the number of clusters.
result Consistency for the number of clusters can be achieved with a properly adapted concentration parameter in a Bayesian setting.

New theory for BNNs with Gaussian priors achieves optimal posterior concentration rates.

problem Lack of theoretical results for BNNs with Gaussian priors.
method New approximation theory for non-sparse DNNs with bounded parameters.
result BNNs with non-sparse general priors can achieve near-minimax optimal posterior concentration rates.

This study assesses risk concentration in MDB portfolios using Monte Carlo simulations.

problem Risk concentration in MDB portfolios of a few borrowers.
method Realistic MDB portfolio simulations and Monte Carlo analysis.
result Current risk adjustments may be overly conservative.

Information concentration of probability measures have important implications in learning theory. Recently, it is discovered that the information content of a log-concave distribution concentrates around their differential entropy, albeit with an unpleasant dependence on the ambient dimension. In this work, we prove th…

2018-02-26abs ↗pdf ↗

A new matrix concentration inequality for random products of matrices.

problem Understanding the behavior of random matrix products under bounded independent positive semidefinite matrices.
method Developed a non-asymptotic concentration inequality for the product of matrices.
result The inequality provides a bound on the deviation of the matrix product from its expected value.

This work explores the characteristics of financial contagion in networks whose links distributions approaches a power law, using a model that defines banks balance sheets from information of network connectivity. By varying the parameters for the creation of the network, several interbank networks are built, in which …

2014-10-09abs ↗pdf ↗

We provide a brief tutorial on the use of concentration inequalities as they apply to system identification of state-space parameters of linear time invariant systems, with a focus on the fully observed setting. We draw upon tools from the theories of large-deviations and self-normalized martingales, and provide both d…

2019-06-27abs ↗pdf ↗

This work achieves exponential concentration in heavy-tailed data over CAT(κ) spaces using the Fréchet median.

problem Achieving robust estimation in heavy-tailed data distributions.
method Developing a concentration bound for the Fréchet median in CAT(κ) spaces.
result Exponential concentration of the Fréchet median in CAT(κ) spaces over heavy-tailed data.

We present a novel notion of outlier, called the Concentration Free Outlier Factor, or CFOF. As a main contribution, we formalize the notion of concentration of outlier scores and theoretically prove that CFOF does not concentrate in the Euclidean space for any arbitrary large dimensionality. To the best of our knowled…

2019-01-14abs ↗pdf ↗

Measurement and management of credit concentration risk is critical for banks and relevant for micro-prudential requirements. While several methods exist for measuring credit concentration risk within institutions, the systemic effect of different institutions' exposures to the same counterparties has been less explore…

2019-05-31abs ↗pdf ↗

The paper analyzes sparse high-dimensional linear regression with random design and unknown error variance, providing adaptiveness and concentration rates.

problem Sparse high-dimensional linear regression with random design and unknown error variance.
method Analysis of posterior concentration rates, employing techniques to address model misspecification.
result Adaptiveness and concentration rates of the posterior for sparse high-dimensional linear regression.

New method uses machine learning to estimate drug parameters in brain models.

problem Estimating unknown parameters in complex brain drug models.
method Physics-Informed Neural Networks (PINNs) for inverse problem solving.
result Accurate parameter estimation leads to precise drug concentration profiles.

In this paper, we study non-asymptotic deviation bounds of the least squares estimator in Gaussian AR(nn) processes. By relying on martingale concentration inequalities and a tail-bound for χ2χ^2 distributed variables, we provide a concentration bound for the sample covariance matrix of the process output. With this, …

2019-12-17abs ↗pdf ↗

Improved concentration inequalities for sub-Weibull variables enhance statistical and machine learning applications.

problem Improving concentration inequalities for sub-Weibull random variables.
method Developed new concentration inequalities for sums of independent sub-Weibull random variables, including a new sub-Weibull parameter.
result New concentration inequalities with sharper constants and a mixture of sub-Gaussian and sub-Weibull tails.

Quantum kernel methods can lead to trivial models due to exponential concentration of kernel values.

problem Exponential concentration of quantum kernel values can lead to trivial models in QML.
method Analyzing the resources needed to accurately estimate quantum kernel values and identifying four sources of concentration.
result Quantum kernel values can be exponentially concentrated, leading to trivial models.

Study improves fractional posterior for 1-bit matrix completion.

problem Estimating a binary matrix from observed entries.
method Fractional posterior approach with low-rank factorization and spectral scaled Student priors.
result Concentration results for fractional posterior, demonstrating effectiveness in matrix recovery.

We give a simple optimistic algorithm for which it is easy to derive regret bounds of O~(tmixSAT)\tilde{O}(\sqrt{t_{\rm mix} SAT}) after TT steps in uniformly ergodic Markov decision processes with SS states, AA actions, and mixing time parameter tmixt_{\rm mix}. These bounds are the first regret bounds in the general, non-epi…

2018-08-06abs ↗pdf ↗

The paper analyzes SMOTE for imbalanced classification, providing theoretical bounds and guidelines.

problem The challenge of imbalanced classification problems, especially with minority classes.
method Theoretical analysis of SMOTE and related oversampling techniques for minority classes.
result Derives concentration and excess risk bounds for SMOTE and kernel-based classifiers.

Our work connects parameter magnitudes and Hessian eigenspaces in deep neural nets.

problem Understanding the relationship between parameter magnitudes and Hessian curvature in deep learning models.
method Developed a matrix-free algorithm based on sketched SVDs to measure similarity between parameter masks and Hessian eigenspaces.
result Top Hessian eigenvectors tend to be concentrated around larger parameters, indicating a connection between parameter magnitudes and loss curvature.

Proposes a new latent variable model for hyperspherical latent spaces.

problem Efficiently modeling heavy-tailed distributions in hyperspherical latent spaces.
method Introduces spherical Cauchy (spCauchy) latent variables and applies Möbius transformations.
result Shows spCauchy recovers vMF geometry in high-concentration limits and avoids complex evaluations.

We study the concentration of NTK for MLPs at EOC, proving finite-width approximation of gradient independence.

problem Understanding the concentration of Neural Tangent Kernel (NTK) for MLPs at the Edge of Chaos (EOC).
method Proved approximate gradient independence holds at finite width, using maximal inequalities to show NTK matrix concentrates around its infinitely wide limit.
result The NTK matrix of MLPs at EOC concentrates around its infinitely wide limit, requiring hidden layer widths to grow quadratically.

Develops a parameter-free SGD algorithm with optimal convergence rate.

problem Optimizing parameters in stochastic convex optimization.
method A novel parameter-free algorithm for SGD with high-probability guarantees and adaptive properties.
result Achieves optimal convergence rate with only a double-logarithmic factor increase compared to known-parameter settings.

The paper proposes methods to identify and sample from mixtures of Mallows models for top-k rankings.

problem Identifying and sampling from mixtures of Mallows models for top-k rankings in a heterogeneous population.
method Efficient sampling algorithms and identifiability proofs for both components of the mixture.
result The identifiability and learnability of the Mallows components' parameters in the mixture.

Let (M,g)(M,g) and (K,κ)(K,κ) be two Riemannian manifolds of dimensions mm and k,k , respectively. Let ωC2(N),ω\in C^2(N), ω>0.ω> 0. The warped product M×ωK M\times _ωK is the (m+k) (m+k)-dimensional product manifold M×KM\times K furnished with metric g+ω2κ. g+ω^2 κ. We prove that the supercritical problem $$-Δ_{g+ω^2 κ}u+h u=u^{ {m+2\over …

2014-01-21abs ↗pdf ↗

Paper addresses concentration of distances for fractional quasi p-norms, identifying conditions for concentration and anti-concentration.

problem Understanding concentration of distances for fractional quasi p-norms in high dimensions.
method Analyzes conditions for concentration and anti-concentration of distances for fractional quasi p-norms.
result Identifies conditions for concentration and anti-concentration of fractional quasi p-norms, ruling out some approaches and specifying conditions for control.

Study Finsler metric measure manifolds' concentration properties.

problem Understanding concentration properties in Finsler metric measure manifolds.
method Established relationships with observable diameter, isoperimetric inequalities, and first eigenvalue.
result Derived a Cheng type upper bound estimate for the first closed eigenvalue.

Method detects effects of synthesis parameters on plutonium oxide microstructure.

problem Detecting effects of synthesis parameters on material microstructure.
method Copula theory, high dimensional distribution distances, and permutational statistics.
result Effects of strike order and oxalic acid feed on plutonium oxide microstructure detected.

We establish a new estimate for the Ginzburg-Landau energies Eε(u)=M12du2+14ε2(1u2)2E_ε(u)=\int_M\frac{1}{2}|du|^2+\frac{1}{4ε^2}(1-|u|^2)^2 of complex-valued maps uu on a compact, oriented manifold MM with b1(M)0b_1(M)\neq 0, obtained by decomposing the harmonic component huh_u of the one-form ju:=u1du2u2du1ju:=u^1du^2-u^2du^1 into an integral and frac…

2017-04-03abs ↗pdf ↗

We propose an input design method for a general class of parametric probabilistic models, including nonlinear dynamical systems with process noise. The goal of the procedure is to select inputs such that the parameter posterior distribution concentrates about the true value of the parameters; however, exact computation…

2019-03-06abs ↗pdf ↗

The study assesses sensitivity to prior choices in Bayesian nonparametric models.

problem Difficulty in specifying priors for Bayesian nonparametric models.
method Utilizes variational Bayesian methods to assess sensitivity to concentration parameter and stick-breaking distribution.
result Demonstrates how to evaluate sensitivity to prior choices in Dirichlet process mixtures and related models.

Study on network-valued processes with asynchronous updates, proving consistency in community and changepoint estimation.

problem Understanding the behavior of network-valued stochastic processes with asynchronous updates.
method Analysis of concentration properties of aggregated adjacency and Laplacian matrices for lazy network-valued stochastic processes.
result Demonstrates consistency of estimators in community and changepoint estimation problems.

We survey recent results related to the concentration of eigenfunctions. We also prove some new results concerning ball-concentration, as well as showing that eigenfunctions saturating lower bounds for L1L^1-norms must also, in a measure theoretical sense, have extreme concentration near a geodesic.

2015-10-26abs ↗pdf ↗