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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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115230344459 · May 202619922001200920172026
48 results for Logarithmic Lower Bounds

Paper proves tight lower bounds for online multicalibration, separating it from marginal calibration.

problem Proving lower bounds for online multicalibration in relation to marginal calibration.
method Information-theoretic approach, constructing group families from orthonormal bases.
result Establishes tight lower bounds for online multicalibration, matching upper bounds up to logarithmic factors.

New bounds for Bayesian bandits show prior improves performance.

problem Improving regret bounds for Bayesian bandits.
method Upper confidence bound algorithm with finite-time logarithmic regret bounds.
result Derives O(cΔlogn)O(c_Δ\log n) and O(chlog2n)O(c_h \log^2 n) upper bounds for Bayesian bandits.

The paper analyzes Q-learning in 2-player Markov games and provides gap-dependent logarithmic regret bounds.

problem Analyzing the cumulative regret of Nash Q-learning in 2-player turn-based stochastic Markov games.
method Proposed gap-dependent logarithmic upper bounds for cumulative regret in episodic tabular setting and discounted game setting.
result The proposed bounds match theoretical lower bounds up to a logarithmic term.

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.

Logarithmic regret for continuous-time reinforcement learning.

problem Continuous-time Markov decision processes with unknown transition probabilities and holding times.
method Upper confidence reinforcement learning, mean holding time estimation, stochastic comparison of point processes.
result Logarithmic regret bound achieved in finite time.

Prove rigidity and classification results for quasilinear Liouville equation on manifolds with nonnegative Ricci curvature.

problem Quasilinear Liouville equation on manifolds with nonnegative Ricci curvature.
method Prove rigidity and classification results for the quasilinear Liouville equation associated with the nn-Laplacian on complete noncompact Riemannian manifolds with nonnegative Ricci curvature.
result Under a sharp logarithmic lower bound, the ambient manifold must be isometric to the Euclidean space and the solution must be one of the standard bubbles.

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 ↗

In this paper, we consider low rank matrix estimation using either matrix-version Dantzig Selector A^λd\hat{A}_λ^d or matrix-version LASSO estimator A^λL\hat{A}_λ^L. We consider sub-Gaussian measurements, i.e.i.e., the measurements X1,,XnRm×mX_1,\ldots,X_n\in\mathbb{R}^{m\times m} have i.i.d.i.i.d. sub-Gaussian entries. Suppose $\textrm…

2014-03-25abs ↗pdf ↗

Study heat flow on changing surfaces, proving existence and uniqueness.

problem Existence and uniqueness of heat flow on time-varying manifolds.
method Establishes estimates for heat flow under minimal assumptions, focusing on logarithmic derivative of volume measure.
result Proves estimates hold for Ricci flow with scalar curvature bounded below, dependent only on initial data.

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.

Lower bounds found for nonconvex-strongly-concave min-max optimization problems.

problem Finding stationary points in nonconvex-strongly-concave min-max optimization.
method Provided lower bounds for first-order oracle complexity.
result Lower bounds of Ω(√κε⁻²) for deterministic oracles and Ω(√κε⁻² + κ¹/₃ε⁻⁴) for stochastic oracles.

We study the Seiberg-Witten equations on surfaces of logarithmic general type. First, we show how to construct irreducible solutions of the Seiberg-Witten equations for any metric which is "asymptotic" to a Poincaré type metric at infinity. Then we compute a lower bound for the L2L^{2}-norm of scalar curvature on these…

2011-12-03abs ↗pdf ↗

Study minimax regret in sequential probability assignment with and without side information.

problem Minimax regret analysis in sequential probability assignment.
method Upper and lower bounds on minimax regret using square-root entropy.
result Lower bound matches upper bound for Donsker classes, up to log factors.

Improved regret bounds for bandits with expert advice.

problem Optimizing decision-making in environments with expert advice.
method Proved lower and upper bounds for regret in restricted and standard feedback models.
result Proved a new upper bound of order KTln(N/K)\sqrt{K T \ln(N/K)} for the worst-case regret, matching a previously known lower bound.

We consider a sequential learning problem with Gaussian payoffs and side information: after selecting an action ii, the learner receives information about the payoff of every action jj in the form of Gaussian observations whose mean is the same as the mean payoff, but the variance depends on the pair (i,j)(i,j) (and may…

2015-10-27abs ↗pdf ↗

Improved GNN simulation of WL test with exponentially lower complexity.

problem Improving the complexity of simulating the Weisfeiler-Lehman test with GNNs.
method Exponentially lower complexity simulation of WL test using GNNs with polylogarithmic parameters and O(log n) bits feature vectors.
result Near-optimal construction with logarithmic lower bounds for feature vector length and neural network size.

Logarithmic regret achieved in RL with linear function approximation.

problem Achieving logarithmic regret in reinforcement learning with linear function approximation.
method LSVI-UCB for linear MDP assumption, UCRL-VTR for linear mixture MDP assumption.
result Logarithmic regret bounds established for RL with linear function approximation.

Optimizes quantile and semi-adversarial regret with novel root-logarithmic regularizers.

problem Minimizes regret in adversarial and semi-adversarial online learning.
method FTRL with root-logarithmic regularizers for quantile and semi-adversarial settings.
result Achieves minimax optimal regret bounds in both paradigms.

New lower bounds for private covariance estimation of Gaussian distributions are proven.

problem Proving tight lower bounds for private estimation tasks under differential privacy.
method Generalized fingerprinting method for exponential families and private Assouad method.
result Tight lower bounds for private covariance estimation in Frobenius and spectral norms.

Lower bounds on Bayes risk for realizable models derived using information theory.

problem Deriving lower bounds on Bayes risk for realizable machine learning models.
method Information-theoretic analysis using rate-distortion theory and mutual information.
result Lower bounds on Bayes risk for realizable models, matching known bounds up to logarithmic factors.

The paper extends statistical estimation techniques under differential privacy.

problem Establishing sample complexity bounds for estimation tasks under differential privacy.
method Proposes analogues of Le Cam's method, Fano's inequality, and Assouad's lemma under central differential privacy.
result Optimal sample complexity bounds for discrete distribution estimation under total variation and 2\ell_2 distances.

The paper sets bounds on how much regret is unavoidable in adaptive LQR with unknown B-matrix.

problem Understanding the limits of adaptive LQR with unknown B-matrix.
method Local asymptotic minimax regret lower bounds using van Trees' inequality and Bellman error representation.
result Logarithmic regret is impossible if the parametrization induces an uninformative optimal policy.

Study shows sample complexity for learning optimal policies in SSP with generative model.

problem Learning optimal policies in Stochastic Shortest Path problems.
method Derive and prove lower and upper bounds on sample complexity.
result Lower bound of Ω(SAB3/(cminε2))Ω(SAB_{\star}^3/(c_{\min}ε^2)) samples for general case, and up to logarithmic factors for bounded hitting time condition.

Smooth finite-sum optimization has been widely studied in both convex and nonconvex settings. However, existing lower bounds for finite-sum optimization are mostly limited to the setting where each component function is (strongly) convex, while the lower bounds for nonconvex finite-sum optimization remain largely unsol…

2019-01-31abs ↗pdf ↗

Unified framework for expert selection with bandit and lower-bound feedback.

problem Selecting the best expert in scenarios with bandit feedback and lower-bound information.
method Introduces a new feedback model combining bandit and lower-bound information, proving optimal regret bounds for modified Exp3 algorithms.
result Optimal regret bounds for modified Exp3 algorithms, generalizing both bandit and full-information settings.

Algorithm approximates functions into manifolds with curvature bounds.

problem Approximating functions into manifolds with lower curvature bounds.
method Algorithm using manifold exponential and logarithm, with error bounds based on sectional curvature.
result Error bounds for nonnegative sectional curvature are similar to linear space approximations.

New algorithms achieve logarithmic regret in learning linear quadratic control systems.

problem Learning in Linear Quadratic Control systems with unknown parameters.
method Efficient algorithms for two scenarios: unknown AA or BB with certain conditions.
result Regret scales logarithmically with the number of steps, not square root.

Nearly all Gaussian points in high dimensions lie on a common ellipsoid.

problem Finding an ellipsoid that fits a large set of Gaussian points in high dimensions.
method Analyzing a random set of Gaussian points and proving a bound on their concentration.
result The bound nearly confirms a conjecture about fitting Gaussian points to ellipsoids.

Lower bounds on MALA and HMC for well-conditioned distributions.

problem Understanding the performance limits of Metropolized sampling methods.
method Analyzing the Metropolis-adjusted Langevin algorithm (MALA) and multi-step Hamiltonian Monte Carlo (HMC) with a leapfrog integrator.
result Nearly-tight lower bound of Ω~(κd)\widetildeΩ(κd) on the mixing time of MALA from an exponentially warm start.