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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.

168,878 papers · 148 categories

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48 results for large aspect ratio

A new algorithm selects independent coordinates for complex manifolds.

problem Embedding algorithms fail with large aspect ratio manifolds.
method IES algorithm selects smooth embeddings using carefully chosen eigenfunctions of the Laplace-Beltrami operator.
result The IES algorithm successfully embeds synthetic and real data.

Paper shows how to embed Möbius bands with many twists and small aspect ratios.

problem Finding the smallest aspect ratio for Möbius bands with many twists.
method Constructs a folded paper ribbon knot to bound the aspect ratio.
result Paper Möbius bands and annuli with any number of half-twists can be embedded with aspect ratio less than 8.

Gradient descent dynamics in nonconvex models explained with universality.

problem Understanding long-time behavior of nonconvex gradient descent.
method Developed a state evolution system for tracking gradient descent iterates.
result Gradient descent iterates are approximately independent of data and strongly incoherent with feature vectors.

The study shows that inscribed rectangles in smooth curves cover at least one third of all possible aspect ratios.

problem Determining the coverage of inscribed rectangles in smooth Jordan curves.
method Analyzing sets of disjoint homologically nontrivial projective planes and applying Kemperman's theorem.
result The Lebesgue measure of the set of aspect ratios is at least 1/3.

New equivalences found between subsampling and ridge regularization methods.

problem Establishing precise structural and risk equivalences between subsampling and ridge regularization.
method Proved structural and risk equivalences between subsample ridge estimators and different ridge regularization levels and subsample aspect ratios.
result Optimally tuned ridge regression exhibits a monotonic prediction risk in the data aspect ratio.

Noise increases the Rashomon ratio, leading simpler models to perform similarly to complex ones.

problem Why simpler models perform similarly to complex models on noisy datasets.
method Analyzed the data generation process and model training choices, introduced pattern diversity.
result Noisier datasets lead to larger Rashomon ratios, explaining simpler models' performance.

The paper analyzes the benefit-cost ratio for feature selection in machine learning.

problem Tackling the challenge of distinguishing relevant features from noise in feature selection.
method Simulation study with different cost and data settings to analyze the benefit-cost ratio.
result The benefit-cost ratio can overemphasize cheap noise features in scenarios with large cost differences and small effect sizes.

Optimizes kernel density ratios for better predictions and information measures.

problem Improving accuracy of kernel density estimates for density ratios.
method Derives an optimal weight function using calculus of variations.
result Reduces bias in kernel density estimates, leading to improved prediction posteriors and information-theoretic measures.

We present an elementary analysis of the dynamical aspects of the GDP / government surplus multiplier with relevance to the assessment of a country's debt repayment policy. We show the (at first) counter intuitive result that in order to reduce the Debt/GDP ratio, countries with high Debt to GDP should go into further …

2013-10-11abs ↗pdf ↗

Solves constant pre-factor problem for tt*-Toda equations using asymptotic data and symplectic structures.

problem Constant pre-factor problem for the tt*-Toda equations.
method Explicit evaluation using asymptotic data and introduction of symplectic structures.
result Preservation of symplectic structures by Riemann-Hilbert correspondence for wider class of solutions.

Importance weighting is a general way to adjust Monte Carlo integration to account for draws from the wrong distribution, but the resulting estimate can be highly variable when the importance ratios have a heavy right tail. This routinely occurs when there are aspects of the target distribution that are not well captur…

2015-07-09abs ↗pdf ↗

PolyModel theory and iTransformer improve hedge fund portfolio construction.

problem Sparse financial time series data makes portfolio construction challenging.
method Identify asset pool, select risk factors, create quantitative and classical measures, and use iTransformer for trend capture.
result Improved Sharpe ratio and annualized return compared to benchmarks.

We present a reinforcement learning approach for detecting objects within an image. Our approach performs a step-wise deformation of a bounding box with the goal of tightly framing the object. It uses a hierarchical tree-like representation of predefined region candidates, which the agent can zoom in on. This reduces t…

2018-10-15abs ↗pdf ↗

Study optimal ridge regularization for out-of-distribution prediction.

problem Optimal ridge regularization for predicting out-of-distribution data.
method Established conditions for optimal regularization under covariate and regression shifts, proving monotonic risk in data aspect ratio.
result Negative regularization can be optimal under shifts, even with isotropic or underparameterized training features.

Paper introduces lexical ratio to measure portfolio diversification.

problem Traditional diversification metrics overlook non-numerical relationships.
method Uses textual data to capture diversification dimensions through entropy-based insights.
result Lexical ratio (LR) outperforms traditional metrics in optimizing portfolio returns.

The paper analyzes the Rashomon ratio for infinite classifier families and shows its importance for choosing good classifiers.

problem Analyzing the Rashomon ratio for infinite classifier families.
method Quantifying the Rashomon ratio in two examples and providing guarantees for estimating it.
result A large Rashomon ratio guarantees choosing a classifier with good empirical accuracy will not significantly increase empirical loss.

It had been believed in the conventional practice that the risk of a bank going bankrupt is lessened in a straightforward manner by transferring the risk of loan defaults. But the failure of American International Group in 2008 posed a more complex aspect of financial contagion. This study presents an extension of the …

2014-09-25abs ↗pdf ↗

We study two aspects of noisy computations during inference. The first aspect is how to mitigate their side effects for naturally trained deep learning systems. One of the motivations for looking into this problem is to reduce the high power cost of conventional computing of neural networks through the use of analog ne…

2018-11-26abs ↗pdf ↗

New algorithm for MDS with quasi-polynomial dependency on aspect ratio.

problem Finding an embedding that minimizes a specific objective function for given dissimilarities.
method A novel geometry-aware analysis of a conditional rounding of the Sherali-Adams LP hierarchy.
result Achieved a solution with cost \(O(\log Δ) \cdot extrm{OPT}^{Ω(1)} + ε\) in quasi-polynomial time.

The systolic ratio of a contact form on a closed three-manifold is the quotient of the square of the shortest period of closed Reeb orbits by the contact volume. We show that every co-orientable contact structure on any closed three-manifold is defined by a contact form with arbitrarily large systolic ratio. This shows…

2017-09-05abs ↗pdf ↗

Direct Density Ratio Optimization aligns LLMs with human preferences without assuming specific models.

problem Statistical inconsistency in aligning LLMs with human preferences.
method Direct Density Ratio Optimization (DDRO) estimates density ratio directly.
result DDRO is statistically consistent, converging to true human preferences as data grows.

Study ridge ensembles in proportional feature-to-sample size regime, proving risk equivalence and GCV consistency.

problem Characterizing and optimizing ridge ensembles in proportional feature-to-sample size regimes.
method Proportional asymptotics analysis, GCV for tuning, proving risk equivalence.
result Risk of optimal full ridgeless ensemble matches optimal ridge predictor's risk.

Let (M,g)(M,g) be a closed, oriented, Riemannian manifold of dimension mm. We call a systole a shortest non-contractible loop in (M,g)(M,g) and denote by sys(M,g)sys(M,g) its length. Let SR(M,g)=sys(M,g)mvol(M,g)SR(M,g)=\frac{{sys(M,g)}^m}{vol(M,g)} be the systolic ratio of (M,g)(M,g). Denote by SR(k)SR(k) the supremum of SR(S,g)SR(S,g) among the surfaces of fixe…

2013-11-06abs ↗pdf ↗

GD with large init shows incremental learning in matrix factorization.

problem Understanding GD's behavior with large initial values in matrix factorization.
method Signal-to-noise ratio concepts and inductive arguments.
result Uncovering an incremental learning phenomenon in GD with large initialization.

Framework mitigates risk non-monotonicity in high-dimensional predictions.

problem Risk non-monotonicity in high-dimensional predictions.
method Model-agnostic framework using cross-validation and data-driven methodologies (zero- and one-step).
result Modified prediction procedures achieve monotonic asymptotic risk behavior.

Proposes a method for ranking items across multiple aspects based on user feedback.

problem No principled solution exists for generating multiple item rankings over different aspects.
method Developed a directional multi-aspect ranking criterion using probabilistic multivariate tensor factorization.
result Demonstrated effectiveness of the proposed method through comprehensive experiments on real datasets.

The book explains deep learning theory and how networks learn nontrivial representations.

problem Understanding and optimizing deep neural networks.
method Developed RG flow to characterize signal propagation, solved layer-to-layer equations, and analyzed representation learning.
result Predictions of trained networks are nearly-Gaussian, with depth-to-width ratio controlling deviations.

Paper optimizes ES estimation under an 1\ell_1 constraint, reducing estimation errors.

problem High instability and infeasibility of ES estimation above a critical ratio r=N/Tr=N/T.
method Analytical approach using the method of replicas from statistical physics.
result Regularization with 1\ell_1 constraint renormalizes the aspect ratio r=N/Tr=N/T.

Estimates Gaussian location model with ridge regularization, comparing variational and spectral methods.

problem Estimating parameters in Gaussian location model with regularization.
method Ridge-regularized log-density-ratio estimation, variational and spectral approaches.
result Regularized variational estimator has lower risk with many observations, spectral estimator with fewer observations.

The paper examines the unexpected losses and risk ratios for co-monotonic alternatives in large portfolios.

problem Understanding the unexpected losses and risk ratios for large portfolios with co-monotonic alternatives.
method Analyzes the asymptotic behavior of unexpected losses and risk ratios for co-monotonic alternatives using monotone cash-additive risk measures and Choquet insurance premia.
result Unexpected losses of large weighted portfolios are of order o(nλn)o(n\overlineλ_n), where λn\overlineλ_n is the average weight.

This paper studies activation sparsity in large language models, finding key trends and implications.

problem Activation sparsity in large language models (LLMs) can be improved for efficiency and interpretability.
method Proposes PPL-p%p\% sparsity, analyzes trends with training data, width-depth ratio, and parameter scale.
result ReLU is more efficient for sparsity than SiLU, and deeper architectures can improve sparsity.

Optimal reinsurance balances risk over surplus ratios for risk-adjusted surplus.

problem Balancing risk over surplus ratios in reinsurance contracts.
method Analyzes reinsurance contracts using Value at Risk and expected surplus ratio, derives simplifications for large portfolios, and considers approximations of the optimum portfolio.
result One or two-layer contracts are optimal for both risk-adjusted surplus and risk over expected surplus ratio, but no second layer for large portfolios or below certain reinsurance prices.

Aggregation defenses improve deep learning models' robustness against data poisoning attacks.

problem Data poisoning attacks manipulate deep learning models with malicious training samples.
method Deep Partition Aggregation, efficiency improvements, data-to-complexity ratio, poisoning overfitting phenomenon.
result Aggregation defenses boost poisoning robustness through the poisoning overfitting phenomenon.

Study introduces new financial ratios for better predicting company performance.

problem Lack of progress in predicting company performance and assessing financial risks.
method Developed new financial and macroeconomic ratios, supervised learning models, and Bayesian models.
result New proposed variables improve model accuracy and FNN performs best across multiple tasks.

This paper addresses privacy concerns in ratio statistics using differential privacy.

problem Privacy concerns in ratio statistics across machine learning areas.
method Develops a simple algorithm for differentially private ratio statistics, proving consistency and constructing confidence intervals.
result A simple algorithm can provide excellent privacy, sample accuracy, and bias properties in ratio statistics.

Adaptive multi-stage density ratio estimation improves learning of latent space EBM.

problem Learning energy-based models in latent space is computationally expensive and challenging.
method Adaptive multi-stage density ratio estimation using NCE to bridge the gap between prior and posterior densities.
result The method enables more expressive prior models and sharpens the latent space EBM.