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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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48 results for crux complex

Convolutional sparse coding (CSC) can learn representative shift-invariant patterns from multiple kinds of data. However, existing CSC methods can only model noises from Gaussian distribution, which is restrictive and unrealistic. In this paper, we propose a general CSC model capable of dealing with complicated unknown…

2019-03-08abs ↗pdf ↗

Low-rank representation~(LRR) has been a significant method for segmenting data that are generated from a union of subspaces. It is, however, known that solving the LRR program is challenging in terms of time complexity and memory footprint, in that the size of the nuclear norm regularized matrix is nn-by-nn (where $…

2015-03-28abs ↗pdf ↗

We show that the basic classification framework alone can be used to tackle some of the most challenging tasks in image synthesis. In contrast to other state-of-the-art approaches, the toolkit we develop is rather minimal: it uses a single, off-the-shelf classifier for all these tasks. The crux of our approach is that …

2019-06-06abs ↗pdf ↗

K. Ding studied a class of Schubert varieties X_λin type A partial flag manifolds, corresponding to integer partitions λand in bijection with dominant permutations. He observed that the Schubert cell structure of X_λis indexed by maximal rook placements on the Ferrers board B_λ, and that the integral cohomology groups …

2004-03-31abs ↗pdf ↗

Solved a conjecture about rational homology projective planes with quotient singularities.

problem A conjecture about rational homology projective planes with quotient singularities.
method Combining Donaldson's diagonalization theorem with a distinguished spin^c structure on the smooth locus.
result Proved that rational homology projective planes with quotient singularities have at most three singular points.

Proposes a method to measure similarity between anomaly scores from different methods.

problem Difficulty in directly comparing anomaly detection methods.
method A measure based on extremal similarity in scoring distributions using a novel upper quadrant modeling approach.
result Demonstrates the ability to detect clusters of anomaly detection algorithms and achieve an accurate ensemble algorithm.

Let G=NAG = N \rtimes A, where NN is a stratified group and A=RA = \mathbb{R} acts on NN via automorphic dilations. Homogeneous sub-Laplacians on NN and AA can be lifted to left-invariant operators on GG and their sum is a sub-Laplacian ΔΔ on GG. Here we prove weak type (1,1)(1,1), LpL^p-boundedness for p(1,2]p \in (1,2]

2018-04-11abs ↗pdf ↗

Trust lies at the crux of most economic transactions, with credit markets being a notable example. Drawing on insights from the literature on coordination games and network growth, we develop a simple model to clarify how trust breaks down in financial systems. We show how the arrival of bad news about a financial agen…

2009-11-16abs ↗pdf ↗

Improved decision tree learning guarantees for complex functions.

problem Achieving provable guarantees for decision tree induction with complex target functions.
method Introduces a new splitting criterion that considers correlations between target function and subsets of attributes.
result Proves provable guarantees for all target functions with respect to the uniform distribution, circumventing previous impossibility results.

The problem of attempting to learn the mapping between data and labels is the crux of any machine learning task. It is, therefore, of interest to the machine learning community on practical as well as theoretical counts to consider the existence of a test or criterion for deciding the feasibility of attempting to learn…

2018-08-20abs ↗pdf ↗

Scoring functions (SFs), which measure the plausibility of triplets in knowledge graph (KG), have become the crux of KG embedding. Lots of SFs, which target at capturing different kinds of relations in KGs, have been designed by humans in recent years. However, as relations can exhibit complex patterns that are hard to…

2019-04-26abs ↗pdf ↗

Transformers learn algorithms for in-context learning with bounds and stability analysis.

problem Understanding and formalizing in-context learning as an algorithm learning problem.
method Formalizing ICL as a multitask learning problem, deriving generalization bounds, and analyzing stability.
result Transformers can implement near-optimal algorithms for classical regression tasks with i.i.d. and dynamic data.

A fundamental task in kernel methods is to pick nodes and weights, so as to approximate a given function from an RKHS by the weighted sum of kernel translates located at the nodes. This is the crux of kernel density estimation, kernel quadrature, or interpolation from discrete samples. Furthermore, RKHSs offer a conven…

2020-02-22abs ↗pdf ↗

Convex clustering is a recent stable alternative to hierarchical clustering. It formulates the recovery of progressively coalescing clusters as a regularized convex problem. While convex clustering was originally designed for handling Euclidean distances between data points, in a growing number of applications, the dat…

2019-11-08abs ↗pdf ↗

Optimizes CM for stochastic convex optimization with progressive precision.

problem Stochastic nature of objective function in convex optimization.
method Iterative coordinate minimization with optimal precision control.
result Order-optimal regret performance for strongly convex and nonsmooth functions.

The paper solves integrable systems of PDEs, including famous equations.

problem Constructing solutions for multicomponent integrable PDEs.
method Reduction to a finite-dimensional system, using Nijenhuis geometry.
result Animations of multi-component soliton and cnoidal solutions.

P-SE explains model decisions with minimal feature subsets and fast estimators.

problem Explain model decisions in regression and classification.
method Probabilistic Sufficient Explanations (P-SE) with random Forests for conditional probability estimation.
result Consistent and efficient explanations for regression and classification models.

In real-world applications, it is important for machine learning algorithms to be robust against data outliers or corruptions. In this paper, we focus on improving the robustness of a large class of learning algorithms that are formulated as low-rank semi-definite programming (SDP) problems. Traditional formulations us…

2019-05-12abs ↗pdf ↗

This paper connects Wasserstein distances to MMD norms for compressive statistical learning.

problem Comparing and controlling Wasserstein distances between probability distributions.
method Establishing conditions under which Wasserstein distances can be controlled by MMD norms.
result Introducing Wasserstein regularity for compressive statistical learning.

A new method improves text generation quality and diversity.

problem Exposure bias in Maximum Likelihood Estimation for text generation.
method ψ-MLE, a new training scheme based on density ratio estimation.
result ψ-MLE outperforms Maximum Likelihood Estimation and other models in text generation quality and diversity.

A novel approach to federated learning with strong privacy guarantees.

problem Maintaining privacy of clients' data and federator's objective in federated learning.
method Inspired by knowledge distillation and private information retrieval, the approach combines secret-sharing-based multi-party computation and graph-based private information retrieval.
result Strong information-theoretic privacy guarantees for federated learning.

Improved MMWU algorithm achieves instance-optimal regret bound for matrix LEA.

problem Matrix Learning from Expert Advice problem.
method Developed a general potential-based framework for matrix LEA, using a new Jensen's trace inequality.
result Achieved instance-optimal regret bound of O(TS(Xd1Id))O(\sqrt{T\cdot S(X||d^{-1}I_d)}).

New findings show that common optimization algorithms struggle with random problems.

problem Finding near-optimal solutions to random optimization problems.
method Low-degree polynomials, Boolean circuits, and Langevin dynamics.
result These algorithms fail to produce nearly optimal solutions with high probability.

Proposes a method to integrate learner models robustly against misspecifications.

problem Misspecifications in learner models and parameter sharing patterns degrade prediction accuracy.
method Sequentially incorporates additional learners based on user-specified parameter sharing patterns.
result Data-adaptively selects the most suitable way of parameter sharing to enhance predictive performance.

Exploiting low-rank structure of the user-item rating matrix has been the crux of many recommendation engines. However, existing recommendation engines force raters with heterogeneous behavior profiles to map their intrinsic rating scales to a common rating scale (e.g. 1-5). This non-linear transformation of the rating…

2018-10-31abs ↗pdf ↗

In various application areas, networked data is collected by measuring interactions involving some specific set of core nodes. This results in a network dataset containing the core nodes along with a potentially much larger set of fringe nodes that all have at least one interaction with a core node. In many settings, t…

2019-05-14abs ↗pdf ↗

Cascading bandit (CB) is a popular model for web search and online advertising, where an agent aims to learn the KK most attractive items out of a ground set of size LL during the interaction with a user. However, the stationary CB model may be too simple to apply to real-world problems, where user preferences may ch…

2019-09-12abs ↗pdf ↗

Deep linear networks oscillate beyond the edge of stability in a predictable manner.

problem Understanding oscillations in deep linear networks beyond the edge of stability.
method Theoretical analysis of loss oscillations in deep matrix factorization loss.
result Loss oscillations in deep linear networks follow a period-doubling route to chaos and occur within a small subspace.

New methods learn sampling distributions for particle filters without supervision.

problem Designing accurate sampling distributions for nonlinear dynamical systems.
method Proposed four unsupervised learning methods for multivariate Gaussian and nonparametric distributions.
result Learned sampling distributions outperform designed ones in accuracy.

MV-GNN improves molecular property prediction by integrating atom and bond information.

problem Accurately predicting molecular properties using graph neural networks.
method Multi-View Graph Neural Network (MV-GNN) architecture with shared self-attentive readout and cross-dependent message passing.
result MV-GNN achieves superior performance on molecular property prediction benchmarks.

Understanding the representational power of Deep Neural Networks (DNNs) and how their structural properties (e.g., depth, width, type of activation unit) affect the functions they can compute, has been an important yet challenging question in deep learning and approximation theory. In a seminal paper, Telgarsky highlig…

2019-12-09abs ↗pdf ↗

A new memory system handles non-stationary environments by self-sizing and retaining memories.

problem Non-stationary environments where memories arrive over time and must be distinguished from noise.
method A self-sizing continual associative memory that generalizes Hopfield's network, handling adaptation and novelty.
result The memory system grows to the intrinsic memory demand of the environment and retains memories without forgetting.

Gradient descent with small initialization solves matrix completion without regularization.

problem Symmetric matrix completion from observed entries.
method Vanilla gradient descent with small initialization.
result GD converges to the ground truth matrix without regularization in over-parameterized scenario.

Algorithm minimizes control regret for non-stationary LQR systems.

problem Control of non-stationary LQR systems with unknown dynamics.
method Adaptive non-stationarity detection and OLS estimator with small bias.
result Achieves optimal dynamic regret of $ ilde{\mathcal{O}}\left(V_T^{2/5}T^{3/5} ight)$.

New research shows no-regret learning is impossible in Markov games under certain assumptions.

problem Achieving no-regret learning in decentralized Markov games.
method Novel application of aggregation techniques from online learning to prove lower bounds.
result No polynomial-time algorithm exists for independent no-regret learning in general-sum Markov games.