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cs.LG2025

Perturbing the Derivative: Doubly Wild Refitting for Model-Free Evaluation of Opaque Machine Learning Predictors

Haichen Hu, David Simchi-Levi

We study the problem of excess risk evaluation for empirical risk minimization (ERM) under convex losses. We show that by leveraging the idea of wild refitting, one can upper bound…

stat.ML2025

Perturbing the Derivative: Wild Refitting for Model-Free Evaluation of Machine Learning Models under Bregman Losses

Haichen Hu, David Simchi-Levi

We study the excess risk evaluation of classical penalized empirical risk minimization (ERM) with Bregman losses. We show that by leveraging the idea of wild refitting, one can eff…

cs.LG2025

Pre-Trained AI Model Assisted Online Decision-Making under Missing Covariates: A Theoretical Perspective

Haichen Hu, David Simchi-Levi

We study a sequential contextual decision-making problem in which certain covariates are missing but can be imputed using a pre-trained AI model. From a theoretical perspective, we…

stat.ML2025

Eluder-Dimension-Free Regret for Stage-Wise Constrained Contextual Bandits via Offline Regression

Haichen Hu, David Simchi-Levi, Navid Azizan

Contextual bandits with stage-wise constraints model decisions that must control risk while learning from their outcomes. We study this problem when only the selected action's rewa…

stat.ML2025

Contextual Online Decision Making with Infinite-Dimensional Functional Regression

Haichen Hu, Rui Ai, Stephen Bates +1

Contextual sequential decision-making problems play a crucial role in machine learning, encompassing a wide range of downstream applications such as bandits, sequential hypothesis…