Lean 4 fork for HoTT-compatible kernel extensions (Path types, transport, HITs). Maintained against upstream leanprover/lean4.
383c0caa91
This PR introduces a new fixpoint combinator, `WellFounded.extrinsicFix`. A termination proof, if provided at all, can be given extrinsically, i.e., looking at the term from the outside, and is only required if one intends to formally verify the behavior of the fixpoint. The new combinator is then applied to the iterator API. Consumers such as `toList` or `ForIn` no longer require a proof that the underlying iterator is finite. If one wants to ensure the termination of them intrinsically, there are strictly terminating variants available as, for example, `it.ensureTermination.toList` instead of `it.toList`. |
||
|---|---|---|
| .claude | ||
| .github | ||
| doc | ||
| images | ||
| releases_drafts | ||
| script | ||
| src | ||
| stage0 | ||
| tests | ||
| .gitattributes | ||
| .gitignore | ||
| .gitpod.Dockerfile | ||
| .gitpod.yml | ||
| .ignore | ||
| CMakeLists.txt | ||
| CMakePresets.json | ||
| CODEOWNERS | ||
| CONTRIBUTING.md | ||
| flake.lock | ||
| flake.nix | ||
| lean-toolchain | ||
| lean.code-workspace | ||
| LICENSE | ||
| LICENSES | ||
| README.md | ||
| RELEASES.md | ||
This is the repository for Lean 4.
About
- Quickstart
- Homepage
- Theorem Proving Tutorial
- Functional Programming in Lean
- Documentation Overview
- Language Reference
- Release notes starting at v4.0.0-m3
- Examples
- External Contribution Guidelines
Installation
See Install Lean.
Contributing
Please read our Contribution Guidelines first.
Building from Source
See Building Lean.