HOL4 vs PVS
| HOL4 | PVS | |
|---|---|---|
| Free plan | No | Yes |
| Free trial | No | No |
| Paid from | — | Free |
| Open source | No | No |
| Platforms | Windows, Linux | Linux, macOS, Windows |
| Free plan | Yes | Yes |
| Supported formalisms | theorem-proving | theorem-proving |
| Counterexamples | Yes | Yes |
| Proof artifacts | Yes | Yes |
| Input languages | HOL higher-order logic; Standard ML | PVS specification language (typed higher-order logic) |
| Deployment | self-hosted | self-hosted |
| Verification method | — | hybrid |
Both are listed in Best Formal Verification Tools. On Freedom251, PVS scores higher on our published basis.