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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.

169,341 papers · 148 categories

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48 results for expander matrices

Convex optimization with expander matrices improves sparse recovery efficiency.

problem Sparse recovery from linear measurements using expander matrices.
method Use of expander matrices for linear sketches in convex optimization to recover block-sparse matrices.
result The recovery error can be expressed in terms of the model-based norm, ensuring the solution is within the model.

We investigate the high-dimensional regression problem using adjacency matrices of unbalanced expander graphs. In this frame, we prove that the 2\ell_{2}-prediction error and the 1\ell_{1}-risk of the lasso and the Dantzig selector are optimal up to an explicit multiplicative constant. Thus we can estimate a high-dim…

2010-10-12abs ↗pdf ↗

TVS-FNNs can approximate any continuous function on expanded input spaces.

problem Processing a broader range of inputs like sequences and matrices.
method Proving a universal approximation theorem for TVS-FNNs.
result TVS-FNNs can approximate any continuous function on expanded input spaces.

We consider high-dimensional quadratic classifiers in non-sparse settings. The target of classification rules is not Bayes error rates in the context. The classifier based on the Mahalanobis distance does not always give a preferable performance even if the populations are normal distributions having known covariance m…

2015-03-16abs ↗pdf ↗

This paper shows universality in spectrum behavior for random inner-product kernel matrices in polynomial regime.

problem Understanding spectrum behavior of random inner-product kernel matrices in polynomial regime.
method Analyzing matrices formed by a nonlinear function applied entrywise to a sample-covariance matrix, considering i.i.d. entries with all finite moments.
result The spectrum of random inner-product kernel matrices is universally described by the free convolution of the semicircular and Marčenko-Pastur distributions, with relative weights given by expanding the nonlinear function in the Hermite basis.

New tail inequalities for sums of random matrices without matrix-dimension terms.

problem Tail behavior of matrix functions in high-dimensional settings.
method Developed new tail inequalities for matrix sums, independent of matrix dimension.
result Tail inequalities for various matrix functions without matrix-dimension terms.

Formula establishes determinant majorization for symmetric matrices.

problem Determining determinant majorization for symmetric matrices.
method Establishes determinant majorization formula for symmetric matrices using invariant Garding-Dirichlet polynomials.
result Formula F(A)1Ndet(A)1nF(A)^{1\over N} \geq \det(A)^{1\over n} for symmetric matrices.

A method for community detection in multilayer networks using data matrices.

problem Community detection in multilayer networks with various node attributes.
method Data matrix representation and regular decomposition method extension for compression.
result Method identifies community structures well-aligned with real-world network hierarchies.

A Bayesian nonparametric approach for continual learning using neural networks.

problem Catastrophic forgetting in neural networks during sequential task settings.
method Indian Buffet Process (IBP) prior for dynamic model expansion and factorization of weight matrices.
result The method promotes positive knowledge transfer between tasks and allows for dynamic model complexity.

Matrix Chernoff bound for Markov chains applied to co-occurrence matrices.

problem Analyzing the behavior of co-occurrence statistics in sequential data.
method Proved a matrix Chernoff-type bound for sums of matrix-valued random variables sampled via a regular Markov chain.
result Achieved exponentially fast convergence rate and sample complexity analysis for co-occurrence matrices.

This paper describes a fast algorithm for recovering low-rank matrices from their linear measurements contaminated with Poisson noise: the Poisson noise Maximum Likelihood Singular Value thresholding (PMLSV) algorithm. We propose a convex optimization formulation with a cost function consisting of the sum of a likeliho…

2014-07-02abs ↗pdf ↗

Sharp curvature estimates for expanding Ricci solitons in various dimensions.

problem Estimating curvature bounds for expanding Ricci solitons.
method Sharp lower and upper bounds derived for scalar curvature under specific conditions.
result Sharp curvature estimates provided for expanding Ricci solitons in dimensions three and four.

Study expanding solitons on complex Lie groups with specific algebraic structures.

problem Investigate expanding solitons on complex Lie groups with left-invariant metrics.
method Analyze the algebraic structure of complex Lie groups and their decompositions.
result Show that the Lie algebras of complex Lie groups decompose into semidirect products.

Compactness proven for specific types of self-expanders in mean curvature flow.

problem Proving compactness for asymptotically conical self-expanders of mean curvature flow.
method Analyzing families of self-expanders and showing compactness in locally smooth topology.
result Properness of the projection map for specified classes of self-expanders.

New degree theory proves existence of solitons on 4D manifolds.

problem Existence of gradient expanding solitons on 4D manifolds.
method Developed new degree theory for 4D, asymptotically conical gradient expanding solitons.
result Existence of solitons asymptotic to any cone over S^3 with non-negative scalar curvature.

Study on the spectrum of drift Laplacian on Ricci expanders.

problem Analyzing the spectrum of the drift Laplacian on Ricci expanders.
method Investigation of discrete spectrum under proper potential function, asymptotic behavior of potential function, and computation of eigenvalues.
result Discrete spectrum of the drift Laplacian on Ricci expanders with bounded Ricci curvature.

Expander graphs have been a focus of attention in computer science in the last four decades. In recent years a high dimensional theory of expanders is emerging. There are several possible generalizations of the theory of expansion to simplicial complexes, among them stand out coboundary expansion and topological expand…

2014-08-27abs ↗pdf ↗

The paper classifies expanding gradient Yamabe solitons based on scalar curvature.

problem Classifying expanding gradient Yamabe solitons based on scalar curvature.
method Rigorous analysis of scalar curvature in both cases: greater than and less than the soliton constant.
result Complete classification of nontrivial complete expanding gradient Yamabe solitons.

Study of complete space-like self-expanders in Minkovski space.

problem Characterize complete space-like self-expanders in Minkovski space.
method Use of maximum principle of Omori-Yau type to prove rigidity theorems.
result Classification of 2-dimensional complete space-like self-expanders with constant squared norm of the second fundamental form.

New algorithm learns stable LDSs with lower error and better control performance.

problem Learning stable LDSs from data with minimal reconstruction error and stability constraints.
method Proposes an optimization method using a recent characterization of stable matrices, iteratively improving reconstruction error and ensuring stability.
result Achieves orders-of-magnitude improvement in reconstruction error compared to existing methods.

Paper develops a decoder for sparse codes without encoder matrix, achieving optimal recovery.

problem Designing a decoder for sparse codes from linear measurements alone.
method Matrix factorization to recover encoder and sparse coding matrices from measurements.
result Decoder-Expander Based Factorisation recovers encoder and sparse coding matrix at optimal measurement rate with high probability.

Enhances sample diversity in SGMCMC for better uncertainty estimation in BNNs.

problem Limited sample diversity in SGMCMC affects uncertainty estimation and model performance.
method Reparameterizes neural network weights to produce a more diverse set of samples.
result The proposed approach achieves superior performance in image classification tasks, including OOD robustness.

We give a cohomological characterisation of expander graphs, and use it to give a direct proof that expander graphs do not have Yu's property A.

2011-08-31abs ↗pdf ↗