AI engineering glossary · Reinforcement learning
What is belief state?
Belief state: A probability distribution over which hidden situations the world might currently be in, updated after each observation using Bayes' rule. It summarises the whole history and turns a partially observed problem into a fully observed one over beliefs.
Belief state: an example
A robot in a corridor with two identical doors holds belief 0.5 for each door until a sensor reading makes it 0.9 for one.
Related terms
More Reinforcement learning terms
- Bellman backup
- Bellman equation
- Bellman optimality equation
- Bootstrapping
- Conservative Q-learning
- Contextual bandit
- Continuing task
- Count-based exploration
Where you learn it
Belief state is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.