Numerical solution of a PDE arising from prediction with expert advice
Document Type
Article
Publication Date
1-1-2025
Abstract
This work investigates the online machine learning problem of prediction with expert advice in an adversarial setting through numerical analysis of, and experiments with, a related partial differential equation. The problem is a repeated two-person game involving decision-making at each step informed by n experts in an adversarial environment. The continuum limit of this game over a large number of steps is a degenerate elliptic equation whose solution encodes the optimal strategies for both players. We develop numerical methods for approximating the solution of this equation in relatively high dimensions (n ≤ 10) by exploiting symmetries in the equation and the solution to drastically reduce the size of the computational domain. Based on our numerical results we make a number of conjectures about the optimality of various adversarial strategies, in particular about the non-optimality of the COMB strategy.
Publication Source (Journal or Book title)
European Journal of Applied Mathematics
Recommended Citation
Calder, J., Drenska, N., & Mosaphir, D. (2025). Numerical solution of a PDE arising from prediction with expert advice. European Journal of Applied Mathematics https://doi.org/10.1017/S0956792525000075