arXiv Machine Learning

Understanding Head Geometry and Dynamics in Federated Regression through a Natural Solution Selection Rule: An Unconstrained Feature Model Analysis

arXiv Machine Learning
Aug 19

Feature Priming in Online Linear Regression: Sparse-Regret Lower Bounds and a Tight Univariate Rate

The paper investigates feature priming in high‑dimensional online linear regression, showing that estimating feature weights from past data and refitting a minimum‑norm predictor can lead to regret that scales with sparsity rather than ambient dimension. It provides a negative answer to a COLT 2023 open problem by proving that three natural priming rules incur ≥Ω(min{T,√d}) regret against a zero‑loss one‑sparse comparator, due to cheap nuisance interpolation that underweights truly predictive coordinates. The authors also identify conditions under which regret is governed by data rank and present constructions that achieve tight univariate rates, while noting that the multivariate case remains unresolved.

By Huibo Xu, Shi Fu, Qixin Zhang, Dacheng Tao
arXiv Machine Learning
Sep 18

FedFIbOS: Fisher Importance based Optimal Submodelling for Heterogeneous Federated Learning

FedFIbOS introduces a Fisher‑importance based criterion for selecting submodel parameters in heterogeneous federated learning, addressing the lack of theoretical justification in prior heuristic methods. By deriving a Fisher‑weighted quadratic masking surrogate and showing that the raw Fisher top‑k rule satisfies this surrogate under a Fisher‑dominant ranking condition, the method preserves convergence guarantees while efficiently estimating Fisher scores from squared gradients. Experiments on CIFAR‑10, CIFAR‑100, and AGNews demonstrate that FedFIbOS outperforms state‑of‑the‑art approaches by roughly 10% in accuracy, especially under strong non‑IID heterogeneity.

By Yasmeen Afzal, Jeremiah D. Deng, Haibo Zhang
arXiv Machine Learning
1d ago

From Task Mixtures to Specialized Experts

The paper investigates federated learning where each client’s data consists of unknown mixtures of distinct tasks, a scenario termed compound heterogeneity. It shows that when tasks share a common feature geometry, the optimal model for a mixed client is a convex combination of task‑specific models, motivating input‑dependent routing to specialized experts. The authors propose FedSEE, a method that recovers task experts via a convex program and achieves better performance than baselines, reducing negative transfer by 2.9 points overall and 3.7 points for the worst‑served quartile.

By Hojat Allah Salehi, Mehrdad Mahdavi, Andrew Arash Mahyari, M. Hadi Amini
arXiv Machine Learning
4d ago

Byzantine-Robust Federated Representation Learning

arXiv:2609.36660v1 Announce Type: new Abstract: We study federated learning (FL) with adversarial clients, where the goal is to minimize the average loss of the honest (non-adversarial) clients witho...

By Leonardo F. Toso, James Anderson, Rafael Pinot, Nirupam Gupta