cvc5 vs Why3
cvc5
cvc5.github.ioWhy3
why3.orgSide by side
| Figure | cvc5 | Why3 |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Formal Verification Tools | 8.7 (#1) | 8.0 (#12) |
| Downloads | The project provides source releases and binaries for Linux, macOS, and Windows, and suggests prebuilt binaries for new users. | The site lists Debian, Fedora, and Ubuntu packages and links to source release 1.8.2. |
| Integrations | The project lists applications using cvc5, including Kind 2 and QMaxUSE as backend solvers, and TRLC through PyVCG for proving absence of runtime errors. | The project lists EasyCrypt, Frama-C, and SPARK 2014 among projects that use Why3. |
| Purpose | cvc5 is an efficient open-source automatic theorem prover for satisfiability modulo theories problems. | Why3 is a platform for deductive program verification that uses WhyML and external theorem provers to discharge verification conditions. |
| Support | The project directs bug reports to its GitHub issue tracker and questions, feature requests, and contributions to GitHub Discussions. | The project provides a user mailing list, a Zulip chat, and a bug tracking system. |
Plans
In their own words
cvc5
cvc5 is a free, open-source solver for satisfiability modulo theories problems. It determines whether first-order formulas are satisfiable or valid across combinations of background theories, including arrays, bit-vectors, floating-point numbers, arithmetic, and strings. It also has a Syntax-Guided Synthesis engine for synthesizing functions against those theories.
The solver can run as a standalone command-line tool or be used as a library, with C++, C, Java, and Python APIs. Its binary accepts SMT-LIB v2 and SyGuS-IF input, and it can produce proofs and unsatisfiable cores to explain unsatisfiability results. The project links to an online interface for running SMT-LIB scripts and provides source releases and binaries for Linux, macOS, and Windows. cvc5 is led jointly by Stanford University and the University of Iowa. Research and commercial use are described as essentially unrestricted. The default license is modified BSD; using optional GPLv3 dependencies makes the combined work subject to GPLv3.
Why3
Why3 is a platform for deductive program verification. It uses WhyML to express programs and specifications, then works with external automated or interactive theorem provers to discharge verification conditions. WhyML supports preconditions, postconditions, assertions, and loop invariants, alongside logical theories and data structures such as arrays, queues, and hash tables. External provers need to be installed and configured separately. Why3 can be extended with support for new provers and used as a software library through its OCaml API. WhyML programs can be extracted automatically into correct-by-construction OCaml programs, and WhyML is also used as an intermediate language for verification of C, Java, Rust, and Ada. TryWhy3 provides a JavaScript version that runs in a browser. Installation options include Opam, Docker, source compilation, and listed Debian, Fedora, and Ubuntu packages. Its graphical interface saves proof attempts and transformations in an XML file and can replay obsolete attempts. Why3 is free and open source under GNU LGPL 2.1 with a special linking exception. Loop invariant inference is a work in progress, and many features remain very limited.