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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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4794141188 · Jun 202019922001200920172026
48 results for Square Nonlinearity

New algorithms estimate Jacobian matrices for large-scale machine learning.

problem Efficiently computing search directions for large nonlinear least squares.
method Exploit low-rank structure in Hessian to estimate Jacobian matrices.
result Two algorithms perform well compared to state-of-the-art methods.

ADMM algorithm solves nonlinear matrix decompositions efficiently.

problem Nonlinear matrix decompositions for various applications.
method Alternating Direction Method of Multipliers (ADMM) for nonlinear matrix factorization.
result The method efficiently solves diverse nonlinear matrix decompositions.

JULIA combines multi-linear and nonlinear models for tensor completion.

problem Complex patterns in real-world tensors require a unified model.
method JULIA unifies multi-linear and nonlinear models with flexible component assignment and efficient alternating optimization.
result JULIA outperforms existing methods in large-scale tensor completion.

Generalization in nonlinear least squares can be studied via algorithmic stability and effective dimension.

problem Generalization in nonlinear least squares models
method Deriving error bounds for local minimizers using algorithmic stability and effective dimension
result Bounds depend on learned geometry rather than parameter count

We learn linear models from nonlinear systems using multiple trajectories and regularization.

problem Identifying linear models from data when the underlying dynamics are nonlinear.
method Multiple trajectories data acquisition followed by regularized least squares.
result Learn linearized dynamics with arbitrarily small error given enough samples.

Agent-based market shows herding cycles with square-root price impact.

problem Understanding herding cycles in agent-based markets.
method Agent-based model with 20,000 retail traders interacting with a single institutional agent.
result Agent discovers multi-cycle predatory strategy with 8-11 complete cycles over 2000 trading days.

Gradient descent on ReLU networks with square loss implicitly favors balanced weights.

problem Understanding implicit regularization in nonlinear neural networks with regression losses.
method Analyzing gradient descent dynamics on ReLU networks with square loss.
result It is impossible to characterize the implicit regularization of ReLU networks with square loss by any explicit function of model parameters.

PGD algorithms solve nonlinear inverse problems with generative priors using noisy measurements.

problem Signal estimation from noisy nonlinear measurements with generative priors.
method Projected gradient descent algorithms for two cases: unknown and known nonlinearity.
result PGD algorithms converge linearly to optimal statistical rates using arbitrary initialization.

The paper provides a non-asymptotic error bound for linear system identification under nonlinear policies.

problem System identification for linear systems with nonlinear and/or time-varying policies under i.i.d. random excitation noises.
method Least square estimation with non-asymptotic error bound for bounded state and action trajectories.
result The error bound is consistent with linear policies and generalizes existing guarantees.

We identify linear models from nonlinear systems with initialization constraints.

problem Identifying linear models from nonlinear systems with initialization constraints.
method Multiple trajectories-based deterministic data acquisition algorithm followed by regularized least squares.
result We provide a finite sample error bound on the learned linearized dynamics.

Spectral decomposition of the Koopman operator is attracting attention as a tool for the analysis of nonlinear dynamical systems. Dynamic mode decomposition is a popular numerical algorithm for Koopman spectral analysis; however, we often need to prepare nonlinear observables manually according to the underlying dynami…

2017-10-12abs ↗pdf ↗

Smooth, globally PŁ functions are essentially nonlinear least-squares.

problem Understanding the structure of functions satisfying the Polyak-Łojasiewicz condition.
method Analyzing smooth functions on Riemannian manifolds with the PŁ condition.
result Smooth, globally PŁ functions are of the form f(x)=f+φ(x)2f(x) = f^* + \|\varphi(x)\|^2.

A new method estimates parameters of complex models using ordinary least squares.

problem Estimating parameters of nonlinear dynamic models from time series data.
method Physics-Informed Regression (PIR) using regularized ordinary least squares.
result PIR outperforms physics-informed neural networks (PINN) in parameter estimation.

The kernel least mean squares (KLMS) algorithm is a computationally efficient nonlinear adaptive filtering method that "kernelizes" the celebrated (linear) least mean squares algorithm. We demonstrate that the least mean squares algorithm is closely related to the Kalman filtering, and thus, the KLMS can be interpreted…

2013-10-20abs ↗pdf ↗

This book introduces linear models and their theories rigorously.

problem Understanding linear models and their theories.
method Explains linear models from three perspectives, introduces maximum likelihood estimation, and proves least squares is the best unbiased linear model.
result Least squares is the best unbiased linear model in terms of mean squared error.

Over the last decade, both the neural network and kernel adaptive filter have successfully been used for nonlinear signal processing. However, they suffer from high computational cost caused by their complex/growing network structures. In this paper, we propose two random Euler filters for complex-valued nonlinear filt…

2018-01-02abs ↗pdf ↗

New tools in nonlinear random matrices improve understanding of the Sum of Squares hierarchy.

problem Improving the Sum of Squares (SoS) hierarchy's performance on average-case problems.
method Developed new tools in nonlinear random matrices and applied them to analyze the SoS hierarchy.
result Subexponential-time SoS lower bounds for various problems, offering evidence for the low-degree likelihood ratio hypothesis.

We study the problem of recovering a structured signal x0\mathbf{x}_0 from high-dimensional data yi=f(aiTx0)\mathbf{y}_i=f(\mathbf{a}_i^T\mathbf{x}_0) for some nonlinear (and potentially unknown) link function ff, when the regressors ai\mathbf{a}_i are iid Gaussian. Brillinger (1982) showed that ordinary least-squares estimate…

2017-12-11abs ↗pdf ↗

Stochastic VB improves nonlinear model inference speed and accuracy.

problem Bayesian inference of nonlinear models from noisy data.
method Stochastic Variational Bayesian (VB) inference for nonlinear models.
result Stochastic VB achieves comparable parameter recovery to analytical solution but is faster.

Unified theory and debiasing framework for random oblique projections in high dimensions.

problem Systematic statistical bias in random oblique projections induced by sampling.
method Unified non-asymptotic theory and debiasing framework.
result Sharp bias--variance characterizations and improved approximation accuracy.

Machine learning can improve 2SLS first stage predictions, but nonlinear methods often introduce bias.

problem Improving the first stage of 2SLS using machine learning.
method Decomposed bias into three components, investigated through simulation.
result Nonlinear machine learning methods can introduce substantial bias in second-stage estimates.

Improved real-time UAV terrain following with RVM-RLS filter.

problem Accurate real-time waypoints estimation under measurement noise in nonlinear, time-varying systems.
method Residual Variance Matching Recursive Least Squares (RVM-RLS) filter guided by RVME criterion.
result Improved waypoints estimation accuracy by approximately 88% compared to benchmarks.

We study parameter estimation and asymptotic inference for sparse nonlinear regression. More specifically, we assume the data are given by y=f(xβ)+εy = f( x^\top β^* ) + ε, where ff is nonlinear. To recover ββ^*, we propose an 1\ell_1-regularized least-squares estimator. Unlike classical linear regression, the correspondin…

2015-11-14abs ↗pdf ↗

It is generally accepted that many time series of practical interest exhibit strong dependence, i.e., long memory. For such series, the sample autocorrelations decay slowly and log-log periodogram plots indicate a straight-line relationship. This necessitates a class of models for describing such behavior. A popular cl…

2007-06-13abs ↗pdf ↗

While conformal transformations of the plane preserve Laplace's equation, Lorentz-conformal mappings preserve the wave equation. We discover how simple geometric objects, such as quadrilaterals and pairs of crossing curves, are transformed under nonlinear Lorentz-conformal mappings. Squares are transformed into curvili…

2013-06-05abs ↗pdf ↗

New method estimates convergence bounds for nonlinear Markov chains.

problem Difficulty in describing properties of nonlinear Markov chains.
method Coupling Markov chains to reconstitute distribution relationships and estimate convergence bounds.
result Estimation of convergence bounds is more precise than existing results.

In deep learning, \textit{depth}, as well as \textit{nonlinearity}, create non-convex loss surfaces. Then, does depth alone create bad local minima? In this paper, we prove that without nonlinearity, depth alone does not create bad local minima, although it induces non-convex loss surface. Using this insight, we greatl…

2017-02-27abs ↗pdf ↗

The paper proposes a least squares method for binary compressive sampling with low intrinsic dimension signals.

problem Recovering signals from binary measurements with noise and sign flips.
method Least squares decoder for signals with low generative intrinsic dimension.
result The least squares decoder achieves a sharp estimation error of O(klog(Ln)m)O(\sqrt{\frac{k\log (Ln)}{m}}) under certain conditions.

Bayesian method improves online NARMAX model identification.

problem Online identification of nonlinear systems with small sample sizes and low noise.
method Variational Bayesian inference using message passing algorithm for polynomial NARMAX models.
result Variational Bayesian estimator outperforms recursive and offline least-squares methods.

In order to cope with the increased data volumes generated by modern radio interferometers such as LOFAR (Low Frequency Array) or SKA (Square Kilometre Array), fast and efficient calibration algorithms are essential. Traditional radio interferometric calibration is performed using nonlinear optimization techniques such…

2013-03-05abs ↗pdf ↗