A proof repository for formal verification of software

We present a proof repository that provides a uniform theorem proving interface to virtually any first-order theorem prover. Instead of taking the greatest common divisor of features supported by the first-order theorem provers, the design allows us to support any extension of the logic that can be expressed in first-order logic. If a theorem prover has native support for such a logic, this is exploited. If the prover has no such support, the repository automatically uses the first-order encoding of the extension. A built-in proof assistant is provided that allows the user to manually guide the proving process when all provers fail to prove a theorem. To prove sub-theorems, the proof assistant is able to use the repository’s full capabilities. The repository also maintains a database of proven theorems. When a requested theorem has been proved before, the result from the database is re-used instead of reconstructing the proof all over again. To test the repository, we constructed a tool for static verification of a basic programming language. This language is also described in this paper.