LessWrong (30+ Karma)

“Crisp Supra-Decision Processes” by Brittany Gelb


Listen Later

Audio note: this article contains 363 uses of latex notation, so the narration may be difficult to follow. There's a link to the original text in the episode description.

Introduction

In this post, we describe a generalization of Markov decision processes (MDPs) and partially observable Markov decision processes (POMDPs) called crisp supra-MDPs and supra-POMDPs. The new feature of these decision processes is that the stochastic transition dynamics are multivalued, i.e. specified by credal sets. We describe how supra-MDPs give rise to crisp causal laws, the hypotheses of infra-Bayesian reinforcement learning. Furthermore, we discuss how supra-MDPs can approximate MDPs by a coarsening of the state space. This coarsening allows an agent to be agnostic about the detailed dynamics while still having performance guarantees for the full MDP.

Analogously to the classical theory, we describe an algorithm to compute a Markov optimal policy for supra-MDPs with finite time [...]

---

Outline:

(00:22) Introduction

(01:41) Supra-Markov Decision Processes

(01:45) Defining supra-MDPs

(06:55) Supra-bandits

(08:02) Crisp causal laws arising from supra-MDPs and (supra-)RDPs

(19:25) Approximating an MDP with a supra-MDP

(22:42) Computing the Markov optimal policy for finite time horizons

(25:02) Existence of stationary optimal policy

(28:18) Interpreting supra-MDPs as stochastic games

(32:40) Regret bounds for episodic supra-MDPs

(34:16) Supra-Partially Observable Markov Decision Processes

(36:16) Equivalence of crisp causal laws and crisp supra-POMDPs

(37:18) Proof of Proposition 2

(41:21) Acknowledgements

The original text contained 8 footnotes which were omitted from this narration.

---

First published:

September 17th, 2025

Source:

https://www.lesswrong.com/posts/mt82ZhdEsfh6CNYse/crisp-supra-decision-processes

---

Narrated by TYPE III AUDIO.

---

Images from the article:

__T3A_INLINE_LATEX_PLACEHOLDER___n___T3A_INLINE_LATEX_END_PLACEHOLDER__ for "do nothing." In some cases, the transition probabilities are precisely specified. In other cases, credal sets (notated here by intervals) over the two-element state space describe the transition probabilities." style="max-width: 100%;" />

Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.

...more
View all episodesView all episodes
Download on the App Store

LessWrong (30+ Karma)By LessWrong


More shows like LessWrong (30+ Karma)

View all
The Daily by The New York Times

The Daily

112,664 Listeners

Astral Codex Ten Podcast by Jeremiah

Astral Codex Ten Podcast

130 Listeners

Interesting Times with Ross Douthat by New York Times Opinion

Interesting Times with Ross Douthat

7,216 Listeners

Dwarkesh Podcast by Dwarkesh Patel

Dwarkesh Podcast

530 Listeners

The Ezra Klein Show by New York Times Opinion

The Ezra Klein Show

16,132 Listeners

AI Article Readings by Readings of great articles in AI voices

AI Article Readings

4 Listeners

Doom Debates by Liron Shapira

Doom Debates

14 Listeners

LessWrong posts by zvi by zvi

LessWrong posts by zvi

2 Listeners