# Page Not Found

The URL `~/files/v0/b/gitbook-28427.appspot.com/o/assets/-LQlJLECo8fSZIbzAshb/-LQlO4IvpK1w0Y9Unen3/-LQlXJC6IBhQQxwHKSv3/image.png` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [Importance Sampling](https://dnddnjs.gitbook.io/rl/chapter-7-off-policy-control/importance-sampling.md)
- [Q Learning](https://dnddnjs.gitbook.io/rl/chapter-7-off-policy-control/q-learning.md)
- [Policy Gradient](https://dnddnjs.gitbook.io/rl/chapter-10-policy-gradient/policy-gradient.md)
- [Bellman Optimality Equation](https://dnddnjs.gitbook.io/rl/chapter-3-bellman-equation/bellman-optimality-equation.md)
- [Bellman Expectation Equation](https://dnddnjs.gitbook.io/rl/chapter-3-bellman-equation/bellman-expectation-equation.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://dnddnjs.gitbook.io/rl/chapter-7-off-policy-control/importance-sampling.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://dnddnjs.gitbook.io/rl/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://dnddnjs.gitbook.io/rl/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/rl/chapter-7-off-policy-control/importance-sampling.md`).

You may also use `Accept: text/markdown` header for content negotiation.