HOL4
6.5#7 in formal verification toolsFree planFree planLinuxmacOSSelf-hostedWindows
VisitHOL4 vs Lean
What both publish
| Fact | HOL4 | Lean |
|---|---|---|
| Automation | Built-in decision procedures and theorem provers can automatically establish many simple theorems. | The site highlights the Grind tactic for handling pattern matching and case analysis and solving systems of linear inequalities. |
| License | HOL is free software released under the Modified (3-clause) BSD licence. | Lean is released under the Apache 2.0 license, which the documentation describes as allowing others to use and extend the code and mathematical libraries freely. |
| Support | The community offers help through a mailing list and Zulip chat, while bug reports and feature suggestions go to GitHub issues. | The Lean Community Zulip is described as the central hub for questions and collaboration, and Lean FRO hosts weekly technical office hours. |
HOL4 plans
- HOL4Free
Lean plans
- Lean 4Free
Pick HOL4 if…
HOL4 suits users working on higher-order logic theorem proving, proof tools, or property checking. It may also suit projects that need to connect proof work with external SMT or BDD tools.
Pick Lean if…
Lean suits programmers, theorem provers, and mathematicians working with formalization, proof checking, or software verification. Its general coding capability and browser version may also suit users exploring Lean before choosing a local setup.