On-line Learning in Tree MDPs by Treating Policies as Bandit Arms

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Shah, Anvay, Anandanarayanan, Ramsundar, Moharir, Sharayu, Kalyanakrishnan, Shivaram
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866918486180102144
author Shah, Anvay
Anandanarayanan, Ramsundar
Moharir, Sharayu
Kalyanakrishnan, Shivaram
author_facet Shah, Anvay
Anandanarayanan, Ramsundar
Moharir, Sharayu
Kalyanakrishnan, Shivaram
contents A Tree Markov Decision Problem (T-MDP) is a finite-horizon MDP with a starting state $s_{1}$, in which every state is reachable from $s_{1}$ through exactly one state-action trajectory. T-MDPs arise naturally as abstractions of decision making in sequential games with perfect recall, against stationary opponents. We consider the problem of on-line learning in T-MDPs, both in the PAC and the regret-minimisation regimes. We show that well-known bandit algorithms -- \textsc{Lucb} and \textsc{Ucb} -- can be applied on T-MDPs by treating each policy as an arm. The apparent technical challenge in this approach is that the number of policies is exponential in the number of states. Our main innovation is in the design of confidence bounds based on data shared by the policies, so that the bandit algorithms can yet be implemented with polynomial memory and per-step computation. We obtain instance-dependent upper bounds on sample complexity and regret that sum a ``gap term'' from every terminal state, rather than every policy. Empirically, our algorithms consistently outperform available alternatives on a suite of hidden-information games.
format Preprint
id arxiv_https___arxiv_org_abs_2605_04979
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On-line Learning in Tree MDPs by Treating Policies as Bandit Arms
Shah, Anvay
Anandanarayanan, Ramsundar
Moharir, Sharayu
Kalyanakrishnan, Shivaram
Artificial Intelligence
Machine Learning
A Tree Markov Decision Problem (T-MDP) is a finite-horizon MDP with a starting state $s_{1}$, in which every state is reachable from $s_{1}$ through exactly one state-action trajectory. T-MDPs arise naturally as abstractions of decision making in sequential games with perfect recall, against stationary opponents. We consider the problem of on-line learning in T-MDPs, both in the PAC and the regret-minimisation regimes. We show that well-known bandit algorithms -- \textsc{Lucb} and \textsc{Ucb} -- can be applied on T-MDPs by treating each policy as an arm. The apparent technical challenge in this approach is that the number of policies is exponential in the number of states. Our main innovation is in the design of confidence bounds based on data shared by the policies, so that the bandit algorithms can yet be implemented with polynomial memory and per-step computation. We obtain instance-dependent upper bounds on sample complexity and regret that sum a ``gap term'' from every terminal state, rather than every policy. Empirically, our algorithms consistently outperform available alternatives on a suite of hidden-information games.
title On-line Learning in Tree MDPs by Treating Policies as Bandit Arms
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2605.04979