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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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54108162216 · Jun 202019922001200920172026
48 results for iterated logarithm

This paper tightens the law of the iterated logarithm for empirical KL_inf, applicable to unbounded data.

problem Developing nonasymptotic concentration bounds for empirical KL_inf with optimal constants and rates.
method Presenting a tight law of the iterated logarithm for empirical KL_inf, applicable to unbounded data.
result A tight law of the iterated logarithm for empirical KL_inf, applicable to unbounded data.

Paper analyzes solutions to quasilinear elliptic equations on manifolds using Nash-Moser iteration.

problem Analyzing positive solutions to quasilinear elliptic equations on manifolds with bounded Ricci curvature.
method Employing Nash-Moser iteration technique to derive logarithmic gradient estimates and Liouville properties.
result Derives universal logarithmic gradient estimates for positive solutions under certain conditions.

We give concentration bounds for martingales that are uniform over finite times and extend classical Hoeffding and Bernstein inequalities. We also demonstrate our concentration bounds to be optimal with a matching anti-concentration inequality, proved using the same method. Together these constitute a finite-time versi…

2014-05-12abs ↗pdf ↗

We consider applications of the theory of balanced weight filtrations and iterated logarithms, initiated in arXiv:1706.01073, to PDEs. The main result is a complete description of the asymptotics of the Yang--Mills flow on the space of metrics on a holomorphic bundle over a Riemann surface. A key ingredient in the argu…

2018-02-12abs ↗pdf ↗

We present a new method to solve certain ˉ\bar{\partial}-equations for logarithmic differential forms by using harmonic integral theory for currents on Kahler manifolds. The result can be considered as a ˉ\bar{\partial}-lemma for logarithmic forms. As applications, we generalize the result of Deligne about closedness…

2017-07-31abs ↗pdf ↗

New algorithm achieves logarithmic regret for adversarial online control.

problem Online linear-quadratic control in systems with adversarial disturbances.
method Characterization of optimal offline control law, reduced to online learning with approximate advantage functions.
result First algorithm with logarithmic regret for arbitrary adversarial disturbance sequences.

We give tight concentration bounds for mixtures of martingales that are simultaneously uniform over (a) mixture distributions, in a PAC-Bayes sense; and (b) all finite times. These bounds are proved in terms of the martingale variance, extending classical Bernstein inequalities, and sharpening and simplifying prior wor…

2015-06-22abs ↗pdf ↗

Optimal unimodal fitting for linear loss functions in a sequential, efficient manner.

problem Optimal unimodal transformation of univariate model scores under linear loss functions.
method Proposes a sequential approach to estimate the optimal rectangular fit for observed samples with each new sample.
result Sequential approach achieves optimal efficiency with logarithmic time complexity per iteration.

This paper studies the problem of distributed stochastic optimization in an adversarial setting where, out of the mm machines which allegedly compute stochastic gradients every iteration, an αα-fraction are Byzantine, and can behave arbitrarily and adversarially. Our main result is a variant of stochastic gradient de…

2018-03-23abs ↗pdf ↗

This work improves the convergence theory of diffusion models for generating samples from complex distributions.

problem Improving theoretical understanding of diffusion models, particularly their convergence analysis.
method Developed an instance-dependent convergence rate that adapts to the smoothness of target distributions.
result Established an iteration complexity of min{d,d2/3L1/3,d1/3L}ε2/3\min\{d,d^{2/3}L^{1/3},d^{1/3}L\}\varepsilon^{-2/3} for generating high-quality samples.

New method tackles bilevel optimization with polyhedral constraints.

problem Challenges in bilevel optimization with active-set changes and expensive Hessian inversions.
method Logarithmic barrier smoothing and proxy-gradient algorithm for differentiable approximation.
result Stationarity rates of O(K2/3)O(K^{-2/3}) in deterministic setting and O(K2/5)O(K^{-2/5}) under stochastic noise.

We propose a new algorithmic framework for sequential hypothesis testing with i.i.d. data, which includes A/B testing, nonparametric two-sample testing, and independence testing as special cases. It is novel in several ways: (a) it takes linear time and constant space to compute on the fly, (b) it has the same power gu…

2015-06-10abs ↗pdf ↗

We adopt data structure in the form of cover trees and iteratively apply approximate nearest neighbour (ANN) searches for fast compressed sensing reconstruction of signals living on discrete smooth manifolds. Levering on the recent stability results for the inexact Iterative Projected Gradient (IPG) algorithm and by us…

2017-06-23abs ↗pdf ↗

AIHT improves online high-dimensional quantile regression by separating support discovery and refinement.

problem Online high-dimensional quantile regression with structural sparsity.
method Adaptive Iterative Hard Thresholding (AIHT) alternates stochastic updates with adaptive hard-thresholding steps.
result AIHT achieves logarithmic regret for the sliding-window objective in high-dimensional settings.

A method for estimating parameters from entangled single-sample distributions, robust to high-noise data.

problem Estimating common parameters from entangled single-sample distributions.
method Iterative trimming of samples to estimate the parameter.
result The method can tolerate a constant fraction of high-noise data points.

The paper studies reward concentration in MDPs, covering asymptotic and non-asymptotic settings.

problem Reward concentration in Markov Decision Processes (MDPs).
method Unified approach to reward concentration in MDPs, including asymptotic and non-asymptotic bounds.
result Rate-equivalent definitions of regret for learning policies.

We consider the entropic regularization of discretized optimal transport and propose to solve its optimality conditions via a logarithmic Newton iteration. We show a quadratic convergence rate and validate numerically that the method compares favorably with the more commonly used Sinkhorn--Knopp algorithm for small reg…

2017-10-18abs ↗pdf ↗

New bounds for online portfolio selection without smoothness assumptions.

problem Online portfolio selection with non-Lipschitz, non-smooth losses.
method Data-dependent bounds using novel smoothness characterizations and FTRL with self-concordant regularizers.
result Achieves logarithmic regrets when data is 'easy' and sublinear worst-case regrets.

Develops a parameter-free SGD algorithm with optimal convergence rate.

problem Optimizing parameters in stochastic convex optimization.
method A novel parameter-free algorithm for SGD with high-probability guarantees and adaptive properties.
result Achieves optimal convergence rate with only a double-logarithmic factor increase compared to known-parameter settings.

The study of random walks on hyperbolic spaces and Teichmüller spaces, proving central limit theorems and geodesic tracking.

problem Analyzing random walks on hyperbolic and Teichmüller spaces.
method Proving central limit theorems and geodesic tracking using finite moments and logarithmic moments.
result Translation lengths of random isometries satisfy a central limit theorem if and only if the random walk has finite second moment.

Paper generalizes VB-FTRL for online learning of quantum states with logarithmic loss.

problem Online learning of quantum states with logarithmic loss.
method Generalizes VB-FTRL algorithm for LL-OLQS with polynomial-time implementation.
result Achieves a regret rate of O(d2log(d+T))O (d^2 \log (d + T)) for LL-OLQS.

Paper refutes conjecture on tensor power iteration convergence in overcomplete models.

problem Understanding convergence of tensor power iteration in overcomplete random tensors.
method Analysis of tensor power iteration dynamics from random initialization.
result Polynomially many steps are necessary for convergence, refutes logarithmic conjecture.

We revisit the question of reducing online learning to approximate optimization of the offline problem. In this setting, we give two algorithms with near-optimal performance in the full information setting: they guarantee optimal regret and require only poly-logarithmically many calls to the approximation oracle per it…

2018-04-20abs ↗pdf ↗

New algorithm resists contamination in high-dimensional regression with optimal performance.

problem Adversarial and measurement errors in high-dimensional data.
method Adversarial Contamination-resistant Iterative Hard Thresholding (AC-IHT) algorithm.
result Achieves minimax near-optimal estimation and signal-adaptive support recovery.

Polyak step size GD reaches final radius of convergence after log iterations.

problem Statistical and computational complexities of Polyak step size GD.
method Generalized smoothness and Lojasiewicz conditions, stability of gradients.
result Polyak step size GD reaches final statistical radius of convergence after logarithmic number of iterations.

Recently, prediction markets have shown considerable promise for developing flexible mechanisms for machine learning. In this paper, agents with isoelastic utilities are considered. It is shown that the costs associated with homogeneous markets of agents with isoelastic utilities produce equilibrium prices correspondin…

2012-06-27abs ↗pdf ↗

We consider the family of constant curvature fiber metrics for a Lefschetz fibration with regular fibers of genus greater than one. A result of Obitsu and Wolpert is refined by showing that on an appropriate resolution of the total space, constructed by iterated blow-up, this family is log-smooth, i.e. polyhomogeneous …

2015-01-16abs ↗pdf ↗

New rule reduces exploration regret to logarithmic, improving bad episode handling.

problem Improving exploration regret in average reward MDPs.
method Replacing Doubling Trick with Vanishing Multiplicative rule in EVI-based algorithms.
result Regret is logarithmic under the new rule, significantly better than linear.

The paper provides new gradient estimates for solutions to a nonlinear elliptic equation on smooth metric measure spaces.

problem Gradient estimates for solutions to a specific nonlinear elliptic equation on smooth metric measure spaces.
method Nash-Moser iteration technique to obtain local gradient estimates.
result New local gradient estimates for positive solutions to the equation.

We study the linear contextual bandit problem with finite action sets. When the problem dimension is dd, the time horizon is TT, and there are n2d/2n \leq 2^{d/2} candidate actions per time period, we (1) show that the minimax expected regret is Ω(dT(logT)(logn))Ω(\sqrt{dT (\log T) (\log n)}) for every algorithm, and (2) introduce a V…

2019-03-30abs ↗pdf ↗

Deviation inequalities and limit laws for random walks on metric spaces.

problem Understanding random walks on metric spaces with contracting isometries.
method Adapting Gouëzel's pivotal time construction to establish deviation inequalities.
result Exponential bounds and limit laws for random walks on mapping class groups and CAT(0) spaces.

We introduce a property of mutation loops, called the sign stability, with a focus on an asymptotic behavior of the iteration of the tropical X\mathcal{X}-transformation. A sign-stable mutation loop has a numerical invariant which we call the cluster stretch factor, in analogy with that of a pseudo-Anosov mapping clas…

2019-11-18abs ↗pdf ↗

Unified analysis of online optimization with self-concordant barriers, improving regret bounds.

problem Online convex optimization with specific loss functions.
method Online mirror descent with self-concordant barriers and logarithmic loss.
result Improved regret bounds for online portfolio selection and quantum state learning.

We consider the problem of strongly-convex online optimization in presence of adversarial delays; in a T-iteration online game, the feedback of the player's query at time t is arbitrarily delayed by an adversary for d_t rounds and delivered before the game ends, at iteration t+d_t-1. Specifically for \algo{online-gradi…

2016-05-20abs ↗pdf ↗

Paper derives convergence rates and confidence intervals for LSA with Markovian noise.

problem Analyzing convergence rates and constructing confidence intervals for LSA with Markovian noise.
method Derives non-asymptotic Berry-Esseen bounds and multiplier block bootstrap procedure.
result Provides O(n1/4)\mathcal{O}(n^{-1/4}) convergence rates and guarantees consistent inference.

Paper tackles community recovery in binary symmetric SBM graphs.

problem Community detection in binary symmetric SBM graphs.
method Proposes a two-stage iterative method using projected power iterations and orthogonal iterations.
result Proposed method can exactly recover communities with high probability in logarithmic sparsity regime.

We study optimal regret bounds for control in linear dynamical systems under adversarially changing strongly convex cost functions, given the knowledge of transition dynamics. This includes several well studied and fundamental frameworks such as the Kalman filter and the linear quadratic regulator. State of the art met…

2019-09-11abs ↗pdf ↗

We analyze the classical EM algorithm for parameter estimation in the symmetric two-component Gaussian mixtures in dd dimensions. We show that, even in the absence of any separation between components, provided that the sample size satisfies n=Ω(dlog3d)n=Ω(d \log^3 d), the randomly initialized EM algorithm converges to an esti…

2019-08-28abs ↗pdf ↗

New algorithms converge faster to Nash equilibrium in zero-sum games with bandit feedback.

problem Learning in zero-sum games with bandit feedback without communication.
method Developed two uncoupled algorithms achieving optimal rate of Ω(T1/4)Ω(T^{-1/4}).
result Achieved optimal rate of Ω(T1/4)Ω(T^{-1/4}) for convergence of policy profiles to Nash equilibrium.