ACL2 vs HOL4
| ACL2 | HOL4 | |
|---|---|---|
| Free plan | No | No |
| Free trial | No | No |
| Paid from | — | — |
| Open source | No | No |
| Platforms | Linux, macOS, self-hosted, Windows | Windows, Linux |
| Free plan | Yes | Yes |
| Verification method | deductive | — |
| Supported formalisms | theorem-proving | theorem-proving |
| Counterexamples | Yes | Yes |
| Proof artifacts | Yes | Yes |
| Input languages | ACL2 logic and a subset of applicative Common Lisp | HOL higher-order logic; Standard ML |
| Deployment | self-hosted | self-hosted |
Both are listed in Best Formal Verification Tools. On Freedom251, ACL2 scores higher on our published basis.