Research
On-device research index

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

Trend · papers per month

481216 · Jun 202019922001200920172026
48 results for lookahead Q-function

New RL method learns K-step lookahead Q-functions for fixed-horizon MDPs.

problem Challenges in online reinforcement learning for non-episodic, finite-horizon MDPs.
method Introduces a K-step lookahead Q-function with a time-varying threshold for selecting actions.
result Achieves minimax optimal constant regret for K=1 and O(max((K1),CK1)SATlog(T))\mathcal{O}(\max((K-1),C_{K-1})\sqrt{SAT\log(T)}) regret for K ≥ 2.

We detect lookahead bias in LLM forecasts using a novel statistical method.

problem Detecting lookahead bias in LLM-generated economic forecasts.
method Developed a statistical procedure using date-only recall queries and estimated Lookahead Propensity (LAP).
result LLM forecasts are contaminated with lookahead bias, as indicated by a positive interaction between LAP and the forecast in accuracy regressions.

New algorithm learns optimal policy with multi-step lookahead information.

problem Learning optimal policy in reinforcement learning with multi-step lookahead information is NP-hard.
method Adaptive batching policies that process lookahead in state-dependent chunks.
result Order-optimal regret bounds up to a constant factor of lookahead horizon.

A new Bayesian method optimizes time-dependent expensive functions with lookahead.

problem Maximizing a time-dependent, expensive oracle with limited evaluations.
method Recursive, two-step lookahead expected payoff (r2LEY) acquisition function.
result r2LEY outperforms myopic methods in synthetic and real-world datasets.

The Lookahead optimizer improves SGD's performance and generalization without restrictive assumptions.

problem Improving the generalization of SGD with Lookahead.
method A rigorous stability and generalization analysis of the Lookahead optimizer with minibatch SGD, leveraging on-average model stability.
result Derives generalization bounds for convex and strongly convex problems without the restrictive Lipschitzness assumption, demonstrating a linear speedup with batch size.

A new random forest algorithm uncovers feature interdependencies better than traditional methods.

problem Tackles the sub-optimality of greedy decision tree implementations in random forests.
method Presented a 'stepwise lookahead' variation of random forests that considers multiple split nodes simultaneously.
result Significantly outperforms greedy random forests in uncovering feature interdependencies, especially in high-noise environments.

The vast majority of successful deep neural networks are trained using variants of stochastic gradient descent (SGD) algorithms. Recent attempts to improve SGD can be broadly categorized into two approaches: (1) adaptive learning rate schemes, such as AdaGrad and Adam, and (2) accelerated schemes, such as heavy-ball an…

2019-07-19abs ↗pdf ↗

Magnitude-based pruning is one of the simplest methods for pruning neural networks. Despite its simplicity, magnitude-based pruning and its variants demonstrated remarkable performances for pruning modern architectures. Based on the observation that magnitude-based pruning indeed minimizes the Frobenius distortion of a…

2020-02-12abs ↗pdf ↗

DatedGPT prevents lookahead bias in financial forecasting models.

problem Lookahead bias in large language models trained on internet-scale data.
method Time-aware pretraining with annual data cutoffs and instruction fine-tuning.
result Models' knowledge is effectively bounded by their data cutoff year, improving forecasting validity.

Efficiently optimizes expensive functions with multi-step lookahead using one-shot optimization.

problem Optimizing expensive functions with long-term impacts using myopic approaches.
method Formulated as nested optimization problems within a multi-step scenario tree, optimized in one-shot fashion.
result Multi-step expected improvement is computationally tractable and outperforms existing methods.

Real Time Dynamic Programming (RTDP) is an online algorithm based on Dynamic Programming (DP) that acts by 1-step greedy planning. Unlike DP, RTDP does not require access to the entire state space, i.e., it explicitly handles the exploration. This fact makes RTDP particularly appealing when the state space is large and…

2019-09-10abs ↗pdf ↗

This paper provides fast estimates for complex option types.

problem Estimating prices for constrained multiple exercise American options.
method Lookahead search for lower estimates and nearest-neighbor martingale for upper estimates.
result Probabilistic convergence guarantees for the algorithms.

A new algorithm reduces sample complexity for learning Q-functions in reinforcement learning.

problem Efficiently learning Q-functions in reinforcement learning with continuous state and action spaces.
method Developed a simple, iterative learning algorithm that estimates low-rank Q-functions.
result Achieved exponential improvement in sample complexity for low-rank Q-functions.

Transforms game optimization dynamics into frequency domain for precise hyperparameter analysis.

problem Analyzing convergence of hyperparameters in game optimization.
method Frequency-domain framework using High-Resolution Differential Equations (HRDEs) and Laplace transforms.
result Derives precise convergence criteria for the Lookahead algorithm.

Look-Ahead-Bench evaluates financial LLMs for lookahead bias, revealing significant differences in model performance.

problem Measuring and mitigating lookahead bias in financial LLMs.
method Standardized benchmark evaluating model behavior in practical financial scenarios, analyzing performance decay across market regimes.
result Standard LLMs exhibit significant lookahead bias, while Pitinf models show improved generalization and reasoning abilities.

Introduces lookahead counterfactual fairness to account for downstream effects of ML predictions.

problem Downstream effects of ML predictions on individuals not considered by counterfactual fairness.
method Introduces lookahead counterfactual fairness (LCF), a new fairness notion that considers future status. Proposes an algorithm based on theoretical conditions.
result Proposes an algorithm to achieve lookahead counterfactual fairness and validates it on synthetic and real data.

Chronologically consistent models maintain accuracy with time-restricted data.

problem Training data introduces lookahead bias and training leakage in large language models.
method ChronoBERT and ChronoGPT trained with only available data at each time point.
result Models achieve strong performance and competitive with larger models, mitigating lookahead bias.

SAVO actor improves reinforcement learning by avoiding local optima in complex Q-functions.

problem Gradient ascent in complex Q-functions leads to suboptimal solutions.
method SAVO actor generates multiple action proposals and truncates poor local optima.
result SAVO actor finds optimal actions more frequently and outperforms other architectures.

The paper introduces a new method for estimating optimal policies in dynamic treatment regimes using information geometry.

problem Estimating optimal policies in dynamic treatment regimes.
method Minimum information divergence method based on γγ-power divergence.
result The γγ-power divergence method effectively seeks the optimal policy by vanishing the divergence between policy-equivalent Q-functions.

Study on QQ-function estimation for continuous state-action MDPs, deriving rates and conditions.

problem Estimating QQ-function in off-policy evaluation for continuous state-action Markov decision processes.
method Reformulated as nonparametric instrumental variables (NPIV) problem, derived minimax lower bounds, proposed sieve two-stage least squares estimator.
result First minimax lower bounds for QQ-function and its derivatives in sup-norm and L2L^2-norm, same as classical nonparametric regression.

This paper shows ARMs and EBMs are equivalent, revealing ARM lookahead capabilities.

problem Understanding the lookahead capabilities of next-token prediction models.
method Unified view of ARMs and EBMs, establishing a bijection and deriving equivalence.
result ARMs and EBMs are equivalent, revealing ARM lookahead capabilities.

Efficiently optimizes constrained problems with two-step lookahead BO.

problem Optimizing constrained problems with limited computational resources.
method Two-step lookahead Bayesian optimization with inequality constraints, using a novel unbiased gradient estimator.
result Significantly improves query efficiency over previous methods.

New algorithms estimate Q-functions under partial coverage and realizability, improving offline RL guarantees.

problem Offline RL with limited exploration and assumptions about data coverage and Q-function realizability.
method Proposes minimax learning algorithms to estimate soft or vanilla Q-functions with L2L^2-convergence guarantees.
result PAC guarantees for offline RL under partial coverage and realizability conditions.

Q-learning is one of the most popular methods in Reinforcement Learning (RL). Transfer Learning aims to utilize the learned knowledge from source tasks to help new tasks to improve the sample complexity of the new tasks. Considering that data collection in RL is both more time and cost consuming and Q-learning converge…

2018-09-21abs ↗pdf ↗

Improves DRL for long-term causal inference with semiparametric methods.

problem Efficient inference for policy values in nonparametric MDPs with stringent conditions.
method Semiparametric Double Reinforcement Learning (DRL) with superefficient nonparametric estimators.
result Relaxes overlap conditions and reduces high-dimensional density-ratio estimation.

This paper explores how IV methods can improve Q-function estimates in offline policy evaluation.

problem Confounding in estimating Q-function using reinforcement learning.
method Integrates IV techniques into offline policy evaluation (OPE) to improve Q-function estimates.
result State-of-the-art OPE methods are closely matched in performance by some IV methods.

New methods improve global optimisation for expensive functions using lookahead strategies.

problem Optimising expensive functions without gradient info in high dimensions.
method Nonmyopic acquisition strategies based on approximate dynamic programming.
result Nonmyopic methods outperform myopic approaches in various applications.

We present a new Q-function operator for temporal difference (TD) learning methods that explicitly encodes robustness against significant rare events (SRE) in critical domains. The operator, which we call the κκ-operator, allows to learn a robust policy in a model-based fashion without actually observing the SRE. We i…

2019-01-23abs ↗pdf ↗

The paper proves the convergence of Q-value for Gaussian rewards.

problem Existing proofs cannot guarantee convergence of the Q-function for Gaussian rewards.
method Using the central limit theorem and relaxing the condition to E[r(s,a)2]<E[r(s,a)^2]<\infty.
result Proves the convergence of the Q-function under the condition of E[r(s,a)2]<E[r(s,a)^2]<\infty.

New RL algorithm explains why deep learning works in stochastic environments.

problem Why deep RL algorithms perform well in practice despite using random exploration.
method Introducing SQIRL, an iterative RL algorithm that separates exploration and learning.
result Effective horizon explains why deep RL works in stochastic environments.

We compare the model-free reinforcement learning with the model-based approaches through the lens of the expressive power of neural networks for policies, QQ-functions, and dynamics. We show, theoretically and empirically, that even for one-dimensional continuous state space, there are many MDPs whose optimal QQ-func…

2019-10-14abs ↗pdf ↗