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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.

169,291 papers · 148 categories

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295988117 · Jun 202019922001200920182026
48 results for well-separated clusters

Consistent estimator for mixtures of nonparametric elliptical distributions helps cluster analysis.

problem Consistency of maximum likelihood estimator for mixtures of nonparametric elliptical distributions.
method Maximum likelihood estimation for mixtures of elliptically-symmetric distributions under nonparametric PP.
result Components of the estimator correspond to well-separated components of the underlying distribution PP.

This paper proves t-SNE can recover well-separated clusters, improving visualization and embedding quality.

problem The lack of mathematical foundations and inner workings of t-SNE.
method Proves t-SNE's ability to recover well-separated clusters, using early exaggeration phase and rigorous analysis.
result t-SNE in the early exaggeration phase can be rigorously analyzed and provides novel ways to set parameters.

Study the geometric structure of graph Laplacian embeddings for manifold data.

problem Identifying coarse structure in manifold data sampled from a mixture model.
method Analyze spectral clustering procedure for data sampled from a manifold, focusing on graph Laplacian embeddings.
result Embedded data concentrates on cones centered around orthogonal vectors when the mixture model is well-separated.

We inspect a possible clustering structure of the corruption perception among 134 countries. Using the average linkage clustering, we uncover a well-defined hierarchy in the relationships among countries. Four main clusters are identified and they suggest that countries worldwide can be quite well separated according t…

2015-01-31abs ↗pdf ↗

Algorithm distinguishes Gaussian mixtures from pure Gaussians in quasi-polynomial time.

problem Distinguishing mixtures of Gaussian components from pure Gaussians, especially when components are well-separated.
method Sum-of-Squares method, quasi-polynomial time algorithm, bipartitioning sample to separate components.
result Algorithm can reliably distinguish between mixtures and pure Gaussians in quasi-polynomial time.

Adaptive clustering and personalization algorithms minimize regret in multi-agent stochastic linear bandits.

problem Minimizing regret in a multi-agent stochastic linear bandits framework with user heterogeneity.
method Proposes a novel algorithm that refines cluster identities and minimizes regret, adapting to cluster separation and user parameter deviations.
result Regret scales as O(T/N)\mathcal{O}(\sqrt{T/N}) for well-separated clusters and O(T12+ε/(N)12ε)\mathcal{O}(T^{\frac{1}{2} + \varepsilon}/(N)^{\frac{1}{2} -\varepsilon}) for poorly separated clusters.

New algorithm for private minimum spanning tree release with improved accuracy.

problem Privacy-preserving minimum spanning tree release for graphs.
method Formal differential privacy definition for graphs, new MST algorithm, combining sanitizing mechanism and MST clustering.
result Improved accuracy in weight approximation compared to state of the art.

New clustering algorithm uses reverse nearest neighbour for better density-based clustering.

problem Density-based clustering of separated high-density regions.
method Uses reverse nearest neighbour (RNN) queries to estimate densities and recover clusters.
result Outperforms DBSCAN and ISDBSCAN on synthetic and real-world data.

Sparse subspace clustering (SSC) is an elegant approach for unsupervised segmentation if the data points of each cluster are located in linear subspaces. This model applies, for instance, in motion segmentation if some restrictions on the camera model hold. SSC requires that problems based on the l1l_1-norm are solved …

2016-09-16abs ↗pdf ↗

Paper proposes a novel unsupervised feature selection method using K-means and ADMM.

problem Finding a subset of features for high-dimensional unsupervised learning problems.
method Developed K-means Derived Unsupervised Feature Selection (K-means UFS) using ADMM to solve NP-hard optimization.
result K-means UFS outperforms baselines in feature selection for clustering.

TDA improves FX clustering quality over traditional methods.

problem Capturing complex currency co-movements in FX markets.
method Topological Data Analysis (TDA) compared to traditional statistical methods on monthly FX returns.
result TDA-based clustering yields more compact and well-separated clusters.

A new Wasserstein KK-means method for clustering probability distributions.

problem Clustering probability distributions using the Wasserstein metric.
method Distance-based KK-means with SDP relaxation for Wasserstein barycenters.
result Distance-based KK-means outperforms centroid-based KK-means for clustering probability distributions.

EM algorithm achieves optimal sample complexity for well-separated Gaussian mixtures.

problem Estimating parameters of well-separated Gaussian mixtures.
method New EM convergence proof for well-separated Gaussian mixtures.
result EM algorithm converges with Ω(logk)Ω(\sqrt{\log k}) separation, achieving O(kd/ε2)O(kd/ε^2) samples.

The paper proposes a method to select clusters, models, and algorithms based on quadratic discriminant scores.

problem Selecting the number of clusters, models, and algorithms in cluster analysis.
method Develops quadratic scores for cluster quality, uses bootstrap resampling, and compares partitions.
result The proposed method achieves better overall performance compared to other state-of-the-art methods.

Constructs classifiers for neural networks with specific data configurations.

problem Finding global minima of deep ReLU neural networks on sequentially separable data.
method Explicitly constructs zero loss neural network classifiers using cumulative parameters and truncation maps.
result Global minimizers can be described with a limited number of parameters based on the data structure.

Paper proves noise-tolerant SSC using greedy methods under coherence conditions.

problem Proving noise-tolerant SSC using greedy methods under coherence conditions.
method Derives coherence-based sufficient conditions for correct neighbor identification using MP/OMP in the presence of bounded noise.
result MP/OMP succeed in identifying correct neighbors under certain noise levels, leading to higher clustering accuracy.

Study reveals structure of local minima in GMMs, identifying key cluster centers.

problem Identifying optimal cluster centers in non-convex GMM landscapes.
method Analyzing the negative log-likelihood function of GMMs in the population limit.
result Local minima share a common structure that partially identifies true cluster centers.

A new point process for clustering distributions with repulsion.

problem Clustering distributions with repulsion.
method Distributional Determinantal Point Process (dDPP) with sliced Wasserstein kernel.
result Validated dDPP as a well-defined point process and applied to gene expression and epilepsy data.

Improved sample complexity for Gaussian process approximations.

problem Efficiently approximating Gaussian processes with sparse spectrum.
method Improved sample complexity analysis and auto-encoding algorithm.
result Gaussian process predictions and model evidence can be well-approximated with low sample complexity.

This work introduces a novel method to evaluate generative model novelty.

problem Evaluating the novelty of generative models compared to a reference model.
method Spectral approach to differential clustering and Kernel-based Entropic Novelty (KEN) score.
result The KEN score effectively detects novel modes and compares generative models.

New method estimates density ratio for well-separated distributions using multi-class logistic regression.

problem Challenges in estimating density ratio for well-separated distributions.
method Uses multi-class logistic regression with auxiliary densities to estimate log(p/q).
result Demonstrates superior performance on density ratio estimation, mutual information, and representation learning tasks.

Adversarial online multi-task RL with task separation.

problem Minimize regret in an adversarial online multi-task setting with unknown MDPs.
method Prove minimax and instance-specific lower bounds, develop a clustering algorithm with optimal sample complexity and regret.
result Tight sample complexity and regret bounds for adversarial online multi-task RL.

Single neural network learns multiple tasks from combined data.

problem Can a single neural network learn multiple unrelated tasks?
method Investigates how task representations affect joint learning; uses various task encoding methods.
result Single neural network can learn multiple tasks from combined data, even when tasks are unrelated and different.

At critical coupling, the interactions of Ginzburg-Landau vortices are determined by the metric on the moduli space of static solutions. The asymptotic form of the metric for two well separated vortices is shown here to be expressible in terms of a Bessel function. A straightforward extension gives the metric for N vor…

2002-05-30abs ↗pdf ↗

SGD learns a simple network for multi-class classification from mixtures of well-separated distributions.

problem Learning overparameterized neural networks for multi-class classification.
method Stochastic Gradient Descent (SGD) on structured data.
result SGD learns a network with small generalization error from mixtures of well-separated distributions.

Simple Deep LDA models achieve accuracy competitive with softmax baselines.

problem Training Deep LDA models by maximum likelihood estimation leads to overlapping or collapsed class clusters.
method Proposed a constrained Deep LDA formulation with geometric constraints to fix class means and covariance.
result MLE becomes stable under geometric constraints, yielding well-separated class clusters.

This study examines when non-parametric methods are robust to adversarial examples.

problem Understanding when non-parametric methods are robust to adversarial examples.
method Examined general non-parametric methods and established conditions for r-consistency.
result Non-parametric methods like nearest neighbors and kernel classifiers are r-consistent when data is well-separated, while histograms are not.