Phase 8 · 4 stations

Theory essentials

Where the guarantees come from. Bandit regret is on the Foundations line, where it is read early; this line is the depth behind it, taken to taste.

What you will learn

By now you have used TD, policy gradients and exploration bonuses on faith. Their guarantees exist, and knowing where they hold tells you when an algorithm's failure is a bug and when it is a theorem.

Szepesvári's compact overview, the theory monograph on sample complexity, PAC-MDP and exploration, and the convergence results for TD with function approximation and for policy gradients.

You can state the conditions under which the core algorithms converge, and recognise which of them your agent violates.

Station 1 · track

Szepesvári, 2010

Algorithms for Reinforcement Learning

Compact, rigorous overview of core algorithms and their analysis.

Reference.

Station 2 · track

Agarwal, Jiang, Kakade & Sun, working monograph 2019–2022

Reinforcement Learning: Theory and Algorithms

Sample complexity, PAC-MDP, policy-gradient convergence, exploration theory.

The modern theory reference.

Station 3 · track

Tsitsiklis & Van Roy 1997; Jaakkola, Jordan & Singh 1994

Convergence of TD and Q-learning

TD with function approximation and stochastic-approximation convergence.

Why the deadly triad bites.

Station 4 · track

Agarwal, Kakade, Lee & Mahajan, JMLR 2021

On the Theory of Policy Gradient Methods

Convergence of policy-gradient methods.

Guarantees behind Phase 3.