arXiv Machine Learning

Risk-Averse Wasserstein Distributionally Robust Online Learning

arXiv:2602. 20403v2 Announce Type: replace Abstract: We study distributionally robust online learning, where a risk-averse learner updates decisions sequentially to guard against worst-case distributions drawn from a Wasserstein ambiguity set centered at past observations.

arXiv Machine Learning
Jun 30

Wasserstein Distributionally Robust Regret Optimization

arXiv:2504. 10796v4 Announce Type: replace-cross Abstract: Distributionally robust optimization (DRO) is widely used for decision-making under uncertainty, but its adversarial focus on worst-case loss can lead to overly conservative policies.

By Lukas-Benedikt Fiechtner, Jose Blanchet
arXiv Machine Learning
4d ago

Learning Distributionally Robust First-Order Methods for Convex Optimization

The paper introduces a distributionally robust method for learning hyperparameters of first‑order convex optimization algorithms. By minimizing a Wasserstein‑robust performance estimation problem over a dataset of problem instances, the approach interpolates between classical learning‑to‑optimize (L2O) and worst‑case PEP design. The authors solve the resulting problem with stochastic gradient descent, provide high‑probability risk bounds, and demonstrate that the learned algorithms outperform both worst‑case optimal and vanilla L2O baselines on logistic regression, LASSO, and linear programming tasks.

By Vinit Ranjan, Jisun Park, Bartolomeo Stellato
arXiv AI
Aug 20

Robust Risk Under Evolving Uncertainty: A Wasserstein Counterpart of the Entropic Value-at-Risk

The paper introduces the Wasserstein entropic value-at-risk, a coherent risk measure that replaces the relative-entropy ball of the traditional entropic value-at-risk with an optimal-transport ball. This new measure captures reachable catastrophes that the original entropic measure ignores, and its variational dual mirrors the entropic formula with a transport price replacing inverse temperature. By driving the transport radius with belief entropy, the authors derive a closed‑form robust dynamic‑programming operator whose cautiousness decreases as belief sharpens, providing a certified safety sandwich and a sharp safety switch.

By Deep Kumar Ganguly, Jan K\v{r}et\'insk\'y
arXiv AI
Aug 28

Learning-Augmented Online Allocation under Unreliable Advice: Robustness, Exposure Fairness, and Distribution Shift

The paper introduces a learning‑augmented algorithm for online allocation that handles unreliable predictions. It addresses finite candidate sets, irreversible decisions, and exposure constraints by combining advice with a conservative fallback and a fairness correction. The authors prove consistency and robustness under bounded‑error assumptions and demonstrate experimentally that the method remains stable against adversarial advice while substantially reducing exposure disparity.

By Fredy Pokou (MRE, CRIStAL)