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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.

169,051 papers · 148 categories

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4488131175 · Jun 202019922001200920182026
48 results for Instance Hardness

A new method generates MAX-2-SAT instances with adjustable hardness.

problem Creating hard MAX-SAT instances for evaluating MAX-SAT solvers.
method Inspired by frustrated-loop algorithm, extends to bipartite couplings, tuning hardness through frustration index.
result Generated instances can be tuned through a central parameter (frustration index), showing double phase transition behavior.

HardVis helps visually manage imbalanced data by sampling hard instances.

problem Managing unsafe or noisy instances in imbalanced classification.
method Visual analytics system using undersampling and oversampling techniques.
result Boosts predictive power of ML models by balancing data sets.

In Machine Learning, ensemble methods have been receiving a great deal of attention. Techniques such as Bagging and Boosting have been successfully applied to a variety of problems. Nevertheless, such techniques are still susceptible to the effects of noise and outliers in the training data. We propose a new method for…

2018-04-20abs ↗pdf ↗

Neural model with parameterized algorithms improves graph CO problem solving.

problem Solving NP-hard graph combinatorial optimization problems efficiently and accurately.
method Combining neural models and parameterized algorithms to identify and handle hard and easy parts of CO instances.
result Framework produces superior solution quality and out-of-distribution generalization.

Explicitly constructed 3XOR instances hard for Sum-of-Squares hierarchy.

problem Hard instances for Sum-of-Squares hierarchy.
method Based on high-dimensional expanders (LSV complexes), using cosystolic expansion and local isoperimetric inequality.
result Constructs explicit 3XOR instances hard for O(logn)O(\sqrt{\log n}) levels of Sum-of-Squares hierarchy.

Mathematical Reinforcement Learning faces a 'Two-Hump' problem due to sparse rewards and a scarcity of intermediate 'hard-but-solvable' instances.

problem Mathematical search problems in Reinforcement Learning
method Novel data generation techniques and algorithmic enhancements
result Substantial performance improvements over previous baselines

Study shows challenges in reinforcement learning math problems, proposing enhancements and a hardness measure.

problem Challenges in reinforcement learning finding rare high-reward instances.
method Combining combinatorial group theory, algorithmic enhancements, and topological hardness measure.
result Resolved mathematical questions and proposed enhancements for reinforcement learning.

It is well known that Sparse PCA (Sparse Principal Component Analysis) is NP-hard to solve exactly on worst-case instances. What is the complexity of solving Sparse PCA approximately? Our contributions include: 1) a simple and efficient algorithm that achieves an n1/3n^{-1/3}-approximation; 2) NP-hardness of approximatio…

2015-07-21abs ↗pdf ↗

Learning shrinks hard tail, improving inference performance.

problem Improving inference performance in neural networks.
method Latent Instance Difficulty (LID) model analyzing fine-tuning of neural networks.
result Training-dependent inference scaling, with βexteffβ_ ext{eff} growing with sample size before saturating.

New algorithms minimize regret with multiple best arms in large action spaces.

problem Minimizing regret in multi-armed bandit with multiple best arms.
method Adaptive algorithms that automatically adapt to hardness level, with theoretical regret bounds and lower bounds.
result Proposed algorithms achieve optimal or near-optimal performance, depending on additional knowledge.

Combinatorial auctions are formulated as frustrated lattice gases on sparse random graphs, allowing the determination of the optimal revenue by methods of statistical physics. Transitions between computationally easy and hard regimes are found and interpreted in terms of the geometric structure of the space of solution…

2006-05-25abs ↗pdf ↗

Paper tackles instance-dependent label noise by approximating it with part-dependent noise.

problem Learning with instance-dependent label noise is challenging.
method Approximate instance-dependent label noise with part-dependent noise. Use transition matrices for parts to model noise.
result Method outperforms state-of-the-art approaches for instance-dependent label noise.

A new dynamic attention model improves vehicle routing problem solutions.

problem Vehicle routing problems (VRP) are NP-hard and challenging to solve.
method Dynamic attention model with a dynamic encoder-decoder architecture.
result The model outperforms previous methods and shows good generalization.

Proposes an IRT-based ensemble method to improve machine learning accuracy.

problem Improving the accuracy of machine learning models, especially for hard-to-classify instances.
method Introduces Item Response Theory (IRT) to evaluate sample difficulty and classifier ability, creating three models with different assumptions.
result The proposed IRT ensemble model outperforms other methods on 19 datasets.

Improved hardness results for clearing payments in financial networks with CDSs.

problem Determining clearing payments in financial networks with CDSs after financial shocks.
method Analyzing computational complexity of clearing problems, showing PPAD-hardness and FIXP-completeness improvements.
result PPAD-hardness of clearing problem significantly improved to ε ≈ 0.101.

We prove that the problem of deciding whether a 2- or 3-dimensional simplicial complex embeds into R3\mathbb{R}^3 is NP-hard. Our construction also shows that deciding whether a 3-manifold with boundary tori admits an S3\mathbb{S}^{3} filling is NP-hard. The former stands in contrast with the lower dimensional cases wh…

2017-08-25abs ↗pdf ↗

Paper investigates hardness of learning neural networks under manifold hypothesis.

problem Hardness of learning neural networks under the manifold hypothesis.
method Extending proofs of hardness in the SQ and cryptographic settings to the geometric setting.
result Learning is hard under input manifolds of bounded curvature but learnable with additional assumptions on manifold volume.

We investigate the complexity of finding an embedded non-orientable surface of Euler genus gg in a triangulated 33-manifold. This problem occurs both as a natural question in low-dimensional topology, and as a first non-trivial instance of embeddability of complexes into 33-manifolds. We prove that the problem is NP…

2016-02-25abs ↗pdf ↗

This paper strengthens the computational separation between multimodal and unimodal learning, showing unimodal learning is hard on typical instances.

problem Theoretical justification for empirical success of multimodal machine learning.
method Introduced a stronger average-case computational separation between unimodal and multimodal learning.
result For typical instances, unimodal learning is computationally hard, while multimodal learning is easy.

We present a new anytime algorithm that achieves near-optimal regret for any instance of finite stochastic partial monitoring. In particular, the new algorithm achieves the minimax regret, within logarithmic factors, for both "easy" and "hard" problems. For easy problems, it additionally achieves logarithmic individual…

2012-06-27abs ↗pdf ↗

The restricted isometry property (RIP) for design matrices gives guarantees for optimal recovery in sparse linear models. It is of high interest in compressed sensing and statistical learning. This property is particularly important for computationally efficient recovery methods. As a consequence, even though it is in …

2016-05-31abs ↗pdf ↗

A method learns to solve multilevel combinatorial problems with two players.

problem Multilevel combinatorial optimization problems with multiple players.
method Value-based multi-agent reinforcement learning in a graph neural network framework.
result Close to optimal solutions on graphs up to 100 nodes, with a significant speedup.

Study shows computational hardness can improve adversarial robustness in learning.

problem Developing robust machine learning models against adversarial attacks.
method Investigate if computational limitations of attackers can enhance robustness.
result Demonstrated a learning task where computational robustness outperforms information-theoretic robustness.

New research shows how preconditioning can solve sparse linear regression problems efficiently.

problem Efficiently solving sparse linear regression problems without restrictive conditions.
method Preconditioned Lasso approach to solve sparse linear regression problems.
result Preconditioning can solve a large class of sparse linear regression problems nearly optimally.

Paper estimates optimal classification error with soft labels and calibration.

problem Estimating the optimal classification error with soft labels and calibration.
method Extends previous work on soft labels to estimate Bayes error, addressing bias and corrupted labels.
result The method provides a statistically consistent estimator of the Bayes error, even with imperfectly calibrated soft labels.

Differentiable relaxation for inferring partial orders from noisy linear data.

problem Inference of partial orders from linear data with noisy observations.
method Introducing a differentiable relaxation to model noisy linear extensions, replacing discontinuous precedence and feasibility with smooth surrogates.
result Smooth posterior that preserves partial-order semantics, supports gradient-based inference, and converges to hard likelihood.

Surveying a new method to predict computational hardness in hypothesis testing.

problem Understanding statistical-versus-computational tradeoffs in high-dimensional inference problems.
method The low-degree method, which predicts computational hardness using the second moment of the low-degree likelihood ratio.
result Sharp low-degree lower bounds against subexponential-time algorithms for tensor PCA.

Proposes an online pool generation method for DCS to improve classifier selection accuracy.

problem Difficulty in selecting competent classifiers in dynamic classifier selection techniques.
method Online local pool generation method that considers classification difficulty of samples.
result Significantly greater recognition rates compared to other pool generation methods.

We propose a framework for Semi-Supervised Active Clustering framework (SSAC), where the learner is allowed to interact with a domain expert, asking whether two given instances belong to the same cluster or not. We study the query and computational complexity of clustering in this framework. We consider a setting where…

2016-06-08abs ↗pdf ↗

New method estimates optimal Q-values with better accuracy for specific problems.

problem Estimating optimal Q-values in reinforcement learning is difficult and varies by problem instance.
method Local minimax framework and variance-reduced Q-learning.
result Sharp lower bounds on estimation accuracy for Q-learning.

Paper establishes lower bounds for finite-sum optimization problems using novel construction methods.

problem Lower complexity bounds for finite-sum optimization problems with various component functions.
method Developed novel approach to construct hard instances and analyzed PIFO algorithms.
result Established lower complexity bounds for convex-concave and nonconvex-strongly-concave objectives.

Study shows computational limits for robust classification tasks, leading to cryptographic implications.

problem Computational limitations in learning robust classifiers for classification tasks.
method Extending previous work on statistical/computational tradeoffs, using average-case hard functions and one-way functions.
result Computational hardness of learning robust classifiers even when efficient non-robust classifiers exist.

Annealed Entropic Allocation improves ranking and selection by mitigating hard switching and improving finite-budget discrimination.

problem Sequential budget allocation in ranking and selection
method Annealed weighted soft-min framework
result Surrogate converges uniformly to the hard minimum, soft-min weights concentrate on active challengers, and target allocation map is continuous.

We investigate the relation of two fundamental tools in machine learning and signal processing, that is the support vector machine (SVM) for classification, and the Lasso technique used in regression. We show that the resulting optimization problems are equivalent, in the following sense. Given any instance of an $\ell…

2013-03-05abs ↗pdf ↗

This paper proposes Relational Similarity Machines (RSM): a fast, accurate, and flexible relational learning framework for supervised and semi-supervised learning tasks. Despite the importance of relational learning, most existing methods are hard to adapt to different settings, due to issues with efficiency, scalabili…

2016-08-02abs ↗pdf ↗

Optimal sample complexity for learning Plackett-Luce models.

problem PAC-learning good items from subsetwise feedback in Plackett-Luce models.
method Algorithm based on a wrapper around a PAC winner-finding algorithm, adapting to instance hardness.
result Optimal instance-dependent sample complexity for best arm identification.

Study shows it's impossible to count communities without finding them.

problem Determining the number and sizes of communities in random graph models.
method Hypothesis testing between models with different community structures, using low-degree polynomial framework.
result Testing between two different planted distributions is as hard as finding the communities.

Optimal transport is #P-hard when components are independent, even with approximate solutions.

problem Computational complexity of optimal transport with independent marginals.
method Proved #P-hardness and developed a pseudo-polynomial time approximation algorithm.
result Optimal transport is #P-hard even with independent components and approximate solutions.