Asymptotically free sketched ridge ensembles: Risks, cross-validation, and tuning

P Patil, D LeJeune - arXiv preprint arXiv:2310.04357, 2023 - arxiv.org
We employ random matrix theory to establish consistency of generalized cross validation
(GCV) for estimating prediction risks of sketched ridge regression ensembles, enabling …

Precise asymptotics of bagging regularized m-estimators

T Koriyama, P Patil, JH Du, K Tan, PC Bellec - arXiv preprint arXiv …, 2024 - arxiv.org
We characterize the squared prediction risk of ensemble estimators obtained through
subagging (subsample bootstrap aggregating) regularized M-estimators and construct a …

Optimal Ridge Regularization for Out-of-Distribution Prediction

P Patil, JH Du, RJ Tibshirani - arXiv preprint arXiv:2404.01233, 2024 - arxiv.org
We study the behavior of optimal ridge regularization and optimal ridge risk for out-of-
distribution prediction, where the test distribution deviates arbitrarily from the train …

Asymptotics of resampling without replacement in robust and logistic regression

PC Bellec, T Koriyama - arXiv preprint arXiv:2404.02070, 2024 - arxiv.org
This paper studies the asymptotics of resampling without replacement in the proportional
regime where dimension $ p $ and sample size $ n $ are of the same order. For a given …

The Lasso error is bounded iff its active set size is bounded away from n in the proportional regime

PC Bellec - arXiv preprint arXiv:2501.02601, 2025 - arxiv.org
This note develops an analysis of the Lasso\(\hat b\) in linear models without any sparsity or
L1 assumption on the true regression vector, in the proportional regime where …