arXiv Statistics ML

Decision-Sufficient Posterior Approximation

The paper studies how a posterior approximation must preserve a specific downstream decision problem. It introduces a regret geometry defined by the target posterior and loss, and uses the forward‑Kullback‑Leibler divergence from a baseline approximation to quantify the information needed for action changes. By analyzing the generalized eigenproblem of the regret Hessian and the baseline information metric, the authors derive a tolerance‑dependent effective dimension and show how restricted approximation families can either miss crucial decision directions or incur excess Fisher information costs.

arXiv Machine Learning
Jun 19

Indexed Bellman Information Complexity

arXiv:2606. 11171v2 Announce Type: replace Abstract: We develop indexed Bellman information complexity, a representation-level theory of interactive decision making centered on information indices and reference histories.

By Yunbei Xu
arXiv Machine Learning
Aug 27

Fast rates in Bayesian online learning with approximate posteriors

The paper investigates how fast predictive regret guarantees of exact Bayesian online learning can be maintained when using approximate posterior methods. It establishes a general theorem linking the cumulative cost of posterior approximation to the contraction radius of the exact Gibbs posterior and the Wasserstein distance between approximate and exact posteriors. Three concrete online learning scenarios—linear models, infinite‑dimensional exponential families, and Gaussian process regression—illustrate that appropriately accurate approximations (projected Langevin, truncation, and sparse variational posteriors) preserve fast regret bounds while reducing computational demands.

By Ilsang Ohn
arXiv Machine Learning
Oct 23

The Bayesian Learning Rule Beyond KL Geometry

The paper investigates how the Bayesian Learning Rule (BLR), traditionally tied to Kullback‑Leibler divergence, can be extended to other geometries. It demonstrates that additive BLR updates are possible using mixed‑space Bregman or Fenchel‑Young discrepancies, leading to generalized maximum‑entropy families and new canonical gradient updates. For example, applying the Tsallis negentropy with quadratic statistics yields bounded‑support, heavy‑tailed q‑Gaussian posteriors and a simple Newton‑like implementation, with experiments on CIFAR‑100 showing controllable support and tail behavior and competitive performance.

By Sophia Sklaviadis, Wu Lin, Andre Martins, Mario Figueiredo, Thomas Moellenhoff, Emtiyaz Khan
arXiv Machine Learning
Oct 15

Dimension-Optimal Dynamic Regret in Exp-Concave Online Learning

arXiv:2610.20187v1 Announce Type: new Abstract: Tracking changing comparators is a central problem in online learning. For exp-concave losses, previous work established the $T^{1/3}P_T^{2/3}$ depende...

By Yanyi Li, Wendao Wu, Haihan Zhang, Qinshi Wang, Chenheng Zhang, Chunyuan Zheng, Cong Fang, Haoxuan Li, Zhouchen Lin