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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.

168,695 papers · 148 categories

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4284126168 · May 202619922001200920172026
48 results for separable subspaces

Subspace clustering assumes that the data is sepa-rable into separate subspaces. Such a simple as-sumption, does not always hold. We assume that, even if the raw data is not separable into subspac-es, one can learn a representation (transform coef-ficients) such that the learnt representation is sep-arable into subspac…

2019-12-10abs ↗pdf ↗

This paper presents GRASTA (Grassmannian Robust Adaptive Subspace Tracking Algorithm), an efficient and robust online algorithm for tracking subspaces from highly incomplete information. The algorithm uses a robust l1l^1-norm cost function in order to estimate and track non-stationary subspaces when the streaming data …

2011-09-18abs ↗pdf ↗

A low-rank transformation learning framework for subspace clustering and classification is here proposed. Many high-dimensional data, such as face images and motion sequences, approximately lie in a union of low-dimensional subspaces. The corresponding subspace clustering problem has been extensively studied in the lit…

2013-09-09abs ↗pdf ↗

LOFT separates subspace rotation and transformation for orthogonal fine-tuning.

problem Conflating subspace rotation and transformation in orthogonal fine-tuning.
method LOFT explicitly separates subspace rotation and transformation, using task-aware support selection.
result LOFT recovers principal-subspace orthogonal adaptation and improves efficiency-performance trade-off.

Learning rule consistency tied to non-existence of real-valued measurable cardinals.

problem Consistency of k-NN learning rule in metric spaces.
method Analyzing separable subspaces and density conditions.
result The k-NN classifier's consistency depends on the absence of real-valued measurable cardinals.

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 ↗

For an infinite cardinal κκ let 2(κ)\ell_2(κ) be the linear hull of the standard othonormal base of the Hilbert space 2(κ)\ell_2(κ) of density κκ. We prove that a non-separable convex subset XX of density κκ in a locally convex linear metric space if homeomorphic to the space (i) 2f(κ)\ell_2^f(κ) if and only if XX can be…

2013-05-07abs ↗pdf ↗

Multiple clustering aims at discovering diverse ways of organizing data into clusters. Despite the progress made, it's still a challenge for users to analyze and understand the distinctive structure of each output clustering. To ease this process, we consider diverse clusterings embedded in different subspaces, and ana…

2019-05-10abs ↗pdf ↗

Most existing approaches address multi-view subspace clustering problem by constructing the affinity matrix on each view separately and afterwards propose how to extend spectral clustering algorithm to handle multi-view data. This paper presents an approach to multi-view subspace clustering that learns a joint subspace…

2017-08-29abs ↗pdf ↗

A method for identifying joint and individual subspaces from multi-view data.

problem Unclear conditions for reliably identifying joint and individual subspaces from noisy, high-dimensional measurements.
method Rigorously quantifies conditions based on signal rank, principal angles, and noise levels. Characterizes spectrum perturbations of product of projection matrices.
result Estimates joint and individual subspaces more accurately than existing approaches in simulations and real-world applications.

Discovering and clustering subspaces in high-dimensional data is a fundamental problem of machine learning with a wide range of applications in data mining, computer vision, and pattern recognition. Earlier methods divided the problem into two separate stages of finding the similarity matrix and finding clusters. Simil…

2018-08-28abs ↗pdf ↗

Paper improves 0\ell^{0}-SSC for noisy data by proving SDP and proposing Noisy-DR-0\ell^{0}-SSC.

problem Noisy data and less restrictive subspace affinity in sparse subspace clustering.
method Proposes Noisy-DR-0\ell^{0}-SSC, which projects data onto a lower dimensional space and then applies noisy 0\ell^{0}-SSC.
result Theoretical guarantee on the correctness of noisy 0\ell^{0}-SSC in terms of SDP on noisy data.

In this paper, we propose a novel method for projecting data from multiple modalities to a new subspace optimized for one-class classification. The proposed method iteratively transforms the data from the original feature space of each modality to a new common feature space along with finding a joint compact descriptio…

2019-04-16abs ↗pdf ↗

P-OCS detects OOD samples in a low-dimensional subspace, outperforming existing methods.

problem Efficient OOD detection for deep learning models in open-world environments.
method P-OCS operates in the orthogonal complement of the principal subspace, applying a single projected perturbation.
result P-OCS achieves state-of-the-art OOD detection with negligible computational cost and without requiring model retraining.

The Grassmannian of affine subspaces is a natural generalization of both the Euclidean space, points being zero-dimensional affine subspaces, and the usual Grassmannian, linear subspaces being special cases of affine subspaces. We show that, like the Grassmannian, the affine Grassmannian has rich geometrical and topolo…

2018-07-28abs ↗pdf ↗

Algorithm removes spurious concepts from neural network representations without harming task performance.

problem Spurious correlations hinder neural network out-of-distribution generalization.
method Iterative algorithm that identifies two orthogonal subspaces in neural network representation.
result Algorithm outperforms existing methods on computer vision and natural language processing benchmarks.

Develops a new feature theory for robust machine learning.

problem Creating robust machine learning features from training data.
method Stochastic tensor space feature theory with Karhunen-Loeve expansion and hierarchical subspaces.
result Dramatic increases in accuracy for predicting Alzheimer's disease stages.

EAGC boosts GCD by regulating gradient entanglement, improving known and novel category separability.

problem Gradient entanglement distorts supervised gradients and overlaps known and novel class representations.
method EAGC uses AGA and EEP to align and project gradients, reducing entanglement and overlap.
result EAGC consistently boosts GCD performance, setting new state-of-the-art results.

Two types of nonidentifiability in latent position graphs identified and characterized.

problem Identifying and characterizing nonidentifiability in latent position random graph models.
method Defined and examined subspace nonidentifiability and model-based nonidentifiability, providing examples and characterizing limits.
result Characterized the limits of model-based nonidentifiability and obtained additional limiting results for specific graph models.

In this work we propose a method for reducing the dimensionality of tensor objects in a binary classification framework. The proposed Common Mode Patterns method takes into consideration the labels' information, and ensures that tensor objects that belong to different classes do not share common features after the redu…

2019-02-06abs ↗pdf ↗

The paper extends hypothesis testing to non-diagonalizable matrices, improving network statistics inference.

problem Testing on non-diagonalizable matrices for network statistics.
method Generalizes Wald and t-tests to non-symmetric matrices, controlling convergence rates.
result Improved inference on network statistics from directed networks.

Sparse Subspace Clustering (SSC) is a state-of-the-art method for clustering high-dimensional data points lying in a union of low-dimensional subspaces. However, while 1\ell_1 optimization-based SSC algorithms suffer from high computational complexity, other variants of SSC, such as Orthogonal Matching Pursuit-based S…

2017-08-16abs ↗pdf ↗

The increasing use of multiple sensors, which produce a large amount of multi-dimensional data, requires efficient representation and classification methods. In this paper, we present a new method for multi-dimensional data classification that relies on two premises: 1) multi-dimensional data are usually represented by…

2019-09-04abs ↗pdf ↗

Study pairs of subspaces with or without a common complement in Hilbert spaces.

problem Characterize pairs of subspaces with or without a common complement in Hilbert spaces.
method Analyze pairs of subspaces (S, T) in the Grassmann manifold Gr(H) of a Hilbert space H, identifying Delta and Gamma based on the existence of a common complement.
result Delta is open and its connected components are parametrized by dimension and codimension. Gamma is a C^\infty submanifold characterized by dimensions and semi-Fredholm indices.

Shallow nonlinear networks can separate classes linearly with polynomially scaling width.

problem Understanding the linear separability of deep networks' features.
method Modeling inputs as a union of low-dimensional subspaces and using random weights and quadratic activations.
result Shallow nonlinear networks can achieve linear separation with polynomially scaling width.

The nowadays massive amounts of generated and communicated data present major challenges in their processing. While capable of successfully classifying nonlinearly separable objects in various settings, subspace clustering (SC) methods incur prohibitively high computational complexity when processing large-scale data. …

2015-10-06abs ↗pdf ↗

Poor approximators found in neural networks and random feature models.

problem Understanding why certain neural networks and models perform poorly in approximating functions.
method Established a scale separation of Kolmogorov width type and applied it to neural networks and random feature models.
result Reproducing kernel Hilbert spaces and two-layer neural networks are poor L2L^2-approximators for certain functions.

Meta-learning can perform well on non-convex models even with few samples, contrary to convex models.

problem Understanding the sample complexity of meta-learning for non-convex models.
method Constructing a simple meta-learning instance and analyzing the training dynamics of Reptile and multi-task representation learning.
result Meta-learning can achieve new task sample complexity of O(1)\mathcal{O}(1) for non-convex models, unlike convex models which require Ω(d)Ω(d) samples.

AGOP from KRR recovers central subspace in fewer samples than needed for prediction.

problem Recovering low-dimensional structure in multi-index polynomial functions.
method Fit kernel ridge regression and compute AGOP from the fitted predictor.
result AGOP's top rr eigenspace recovers the central subspace in ndp+δn \asymp d^{p+δ} samples.

This work studies two interrelated problems - online robust PCA (RPCA) and online low-rank matrix completion (MC). In recent work by Candès et al., RPCA has been defined as a problem of separating a low-rank matrix (true data), L:=[1,2,t,,tmax]L:=[\ell_1, \ell_2, \dots \ell_{t}, \dots , \ell_{t_{\max}}] and a sparse matrix (outliers…

2015-03-11abs ↗pdf ↗

We study the problem of distributed multi-task learning with shared representation, where each machine aims to learn a separate, but related, task in an unknown shared low-dimensional subspaces, i.e. when the predictor matrix has low rank. We consider a setting where each task is handled by a different machine, with sa…

2016-03-07abs ↗pdf ↗

Gradient descent converges to perfect classification in neural nets for non-separable data.

problem Classifying linearly non-separable data using neural networks.
method Analysis of gradient descent dynamics in neural networks with sufficient but not large number of neurons.
result Gradient descent converges to global minima with perfect classification in the landscape of minimization problems.

Method estimates multivariate counterfactual distributions efficiently and accurately.

problem Estimating multivariate counterfactual distributions in causal models with correlation structures.
method Proposes a method leveraging a one-dimensional subspace to capture correlation structures and efficiently estimate multivariate counterfactual distributions.
result Demonstrates superior performance over existing methods on synthetic and real-world data.

We formalize causal separation in portfolio theory, deriving a closed-form projected Markowitz solution.

problem Portfolio optimization under causal separation conditions.
method Derive a closed-form solution for portfolio optimization using causal separation conditions.
result A closed-form projected Markowitz solution is derived under causal separation conditions.

Paper proposes CLAIR for efficient LLM fine-tuning across clients.

problem Fine-tuning large language models (LLMs) efficiently and collaboratively.
method Federated LoRA fine-tuning with Collaborative Low-rank Alignment and Identifiable Recovery (CLAIR).
result CLAIR achieves better performance and contamination detection compared to local fine-tuning.