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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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162325487649 · Jun 202019922001200920172026
48 results for self-concordant functions

We study the smooth structure of convex functions by generalizing a powerful concept so-called self-concordance introduced by Nesterov and Nemirovskii in the early 1990s to a broader class of convex functions, which we call generalized self-concordant functions. This notion allows us to develop a unified framework for …

2017-03-14abs ↗pdf ↗

Improved Frank-Wolfe algorithm for generalized self-concordant functions converges quickly.

problem Efficiently solving learning problems with generalized self-concordant objectives.
method Simple Frank-Wolfe variant with open-loop step size strategy γt=2/(t+2)γ_t = 2/(t+2).
result Achieves O(1/t)\mathcal{O}(1/t) convergence rate for primal and Frank-Wolfe gaps.

Many problems in statistical learning, imaging, and computer vision involve the optimization of a non-convex objective function with singularities at the boundary of the feasible set. For such challenging instances, we develop a new interior-point technique building on the Hessian-barrier algorithm recently introduced …

2019-11-04abs ↗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 propose a variable metric framework for minimizing the sum of a self-concordant function and a possibly non-smooth convex function, endowed with an easily computable proximal operator. We theoretically establish the convergence of our framework without relying on the usual Lipschitz gradient assumption on the smooth…

2013-08-13abs ↗pdf ↗

We consider the class of convex minimization problems, composed of a self-concordant function, such as the logdet\log\det metric, a convex data fidelity term h()h(\cdot) and, a regularizing -- possibly non-smooth -- function g()g(\cdot). This type of problems have recently attracted a great deal of interest, mainly due to th…

2014-05-13abs ↗pdf ↗

New insights into natural exponential families improve regret bounds for bandit problems.

problem Improving regret bounds for bandit problems with subexponential tails.
method Proving self-concordance for natural exponential families and applying to bandits.
result Optimistic algorithms for generalized linear bandits have second-order regret bounds that are free of an exponential dependence on problem parameters.

Interior-point methods adapted for manifolds, achieving similar optimization results.

problem Optimizing on manifolds with self-concordant barriers.
method Generalization of self-concordance to Riemannian manifolds, path-following method analysis.
result Local quadratic convergence of Newton's method and standard complexity guarantees.

New bounds on minimax regret for sequential probability assignment using logarithmic loss.

problem Minimizing regret in sequential probability assignment against arbitrary experts.
method Using self-concordance property of logarithmic loss to derive tight bounds.
result Tight bounds on minimax regret for various expert classes.

RHMC improves sampling polytopes defined by inequalities with barriers.

problem Sampling polytopes defined by inequalities efficiently.
method Riemannian Hamiltonian Monte Carlo (RHMC) with a hybrid of Lewis weights and logarithmic barriers.
result RHMC achieves mixing rate of ildeO(m1/3n4/3) ilde O(m^{1/3}n^{4/3}) for polytopes defined by mm inequalities in Rn\R^n.

Improved prediction algorithm for 'easy' sequences with reduced regret.

problem Prediction with expert advice for 'easy' sequences.
method Variant of NormalHedge algorithm using second-order εε-quantile regret bound.
result Second-order εε-quantile regret bound of O(VTlog(VT/ε))O\big(\sqrt{V_T \log(V_T/ε)}\big) for VT>logNV_T > \log N.

Unified meta-algorithm improves average performance across similar tasks in adversarial bandits.

problem Improving performance across multiple similar tasks in adversarial bandit settings.
method Unified meta-algorithm for multi-armed bandits and bandit linear optimization, tuning initialization, step-size, and entropy parameters.
result Unified meta-algorithm yields setting-specific guarantees for MAB and BLO, improving task-averaged regret.

New algorithm reduces prediction errors across various loss functions.

problem Online forecasting algorithms' inability to adapt to different loss functions.
method Design of a novel Follow-the-Perturbed-Leader (FTPL) algorithm with self-concordant noise.
result Simultaneously achieves ildeO(T) ilde O(\sqrt{T}) regret for bounded proper losses and O(logT)O(\log T) regret for bounded smooth proper losses.

The classical asymptotic theory for parametric MM-estimators guarantees that, in the limit of infinite sample size, the excess risk has a chi-square type distribution, even in the misspecified case. We demonstrate how self-concordance of the loss allows to characterize the critical sample size sufficient to guarantee …

2018-10-16abs ↗pdf ↗

Algorithm for online decision making with unknown dynamics and aggregate feedback.

problem Online decision making with unknown dynamics and aggregate bandit feedback.
method Developed an algorithm based on online mirror descent with a self-concordant barrier regularization and an increasing learning rate schedule.
result Achieved O(K)O(\sqrt{K}) regret for the online Markov Decision Process with KK episodes.

The Riemannian Langevin Algorithm samples from manifolds efficiently.

problem Sampling from distributions on manifolds with log-Sobolev inequality.
method Riemannian Langevin Algorithm, log-Sobolev inequality, self-concordance extension, stochastic smoothness bounding.
result The Riemannian Langevin Algorithm converges rapidly to the target density.

Improved confidence bounds for linear logistic model with applications to bandits.

problem Improving confidence bounds for linear logistic model.
method Self-concordant analysis of the logistic loss to avoid dependence on worst-case variance.
result Significant improvement in confidence bounds, avoiding dependence on 1/κ1/κ.

We compute the effect of concordance surgery, a generalization of knot surgery defined using a self-concordance of a knot, on the Ozsváth-Szabó 4-manifold invariant. The formula involves the graded Lefschetz number of the concordance map on knot Floer homology. The proof uses the sutured Floer TQFT, and a version of su…

2018-04-17abs ↗pdf ↗

This article introduces the concepts around Online Bandit Linear Optimization and explores an efficient setup called SCRiBLe (Self-Concordant Regularization in Bandit Learning) created by Abernethy et. al.\cite{abernethy}. The SCRiBLe setup and algorithm yield a O(T)O(\sqrt{T}) regret bound and polynomial run time comple…

2018-05-11abs ↗pdf ↗

This work improves regret minimization for logistic bandits by reducing dependence on a large constant.

problem Minimizing regret in logistic bandits with reduced dependence on a large constant.
method Experimental design procedure and warmup sampling algorithm.
result Achieves a minimax regret of \(O(\sqrt{d \dotμT\log(|\mathcal{X}|)})\) in the fixed arm setting.

New approach for online learning with adaptive adversaries, simpler and more effective.

problem Online learning with adaptive adversaries, especially in bandits and MDPs.
method Uses standard unbiased estimators and a simple increasing learning rate schedule, aided by logarithmically homogeneous self-concordant barriers and strengthened Freedman's inequality.
result First high-probability regret bounds for adversarial bandits and MDPs, resolving open problems.

We propose a stochastic optimization method for minimizing loss functions, expressed as an expected value, that adaptively controls the batch size used in the computation of gradient approximations and the step size used to move along such directions, eliminating the need for the user to tune the learning rate. The pro…

2019-12-31abs ↗pdf ↗

We propose a new proximal, path-following framework for a class of constrained convex problems. We consider settings where the nonlinear---and possibly non-smooth---objective part is endowed with a proximity operator, and the constraint set is equipped with a self-concordant barrier. Our approach relies on the followin…

2016-03-05abs ↗pdf ↗

Study shows fast rates for inverse reinforcement learning with linear rewards.

problem Entropy-regularized min-max inverse reinforcement learning in finite-horizon MDPs.
method Structural and statistical analysis of Min-Max-IRL with pseudo-self-concordance.
result Both trajectory-level KL divergence and parameter error decay at O(n1)\mathcal{O}(n^{-1}).

Popular machine learning estimators involve regularization parameters that can be challenging to tune, and standard strategies rely on grid search for this task. In this paper, we revisit the techniques of approximating the regularization path up to predefined tolerance εε in a unified framework and show that its comp…

2018-10-12abs ↗pdf ↗