The ProB Animator and Model Checker

ProB is an animator, constraint solver and model checker for the B-Method (see the B-Method site of Clearsy). It allows fully automatic animation of B specifications, and can be used to systematically check a specification for a wide range of errors. The constraint-solving capabilities of ProB can also be used for model finding, deadlock checking and test-case generation.

The B language is rooted in predicate logic, arithmetic and set theory and provides support for data structures such as (higher-order) relations, functions and sequences. In addition to the B language, ProB also supports Event-B, CSP-M, TLA+, and Z. ProB can be installed within Rodin, where it comes with BMotionStudio to easily generate domain specific graphical visualizations.

ProB is being used within Siemens, Alstom, and several other companies for data validation of complicated properties for safety critical systems. Commercial support is provided by the spin-off company Formal Mind or by Nobreach. It can be used within Atelier-B as a disprover and prover.

Part of the research and development was conducted within various research projects, such as the EPSRC funded projects ABCD and iMoc, the EU funded projects Rodin, Deploy and Advance as well as the DFG project Gepavas.

Automatically generated test coverage reports are also available.


11/7/2017 ProB 1.7.0 is available. Highlights: improved Latex document generation, improved XML/CSV data import and export, RULE DSL language, many improvements in constraint solver.

20/10/2016 ProB 1.6.1 is available. Highlights: Latex document generation, LET and IF-THEN-ELSE for expressions and predicates, XML logging, performance improvements.

22/4/2016 ProB 1.6.0 is available. Highlights: directed model checking, Z3 available as backend, B line comments and unicode symbols, improved error messages.

19/2/2015 ProB 1.5.0 is available. MC/DC coverage analysis for guards and invariants, improved TLC interface.

3/6/2014 ProB supports Event-B Theories.

30/03/2012 A first version of the online ProB Logic Calculator is available.

More in Release History


The core of ProB is implemented in SICStus Prolog (but can be run without a SICStus Prolog license). The ProB constraint solver is implemented using co-routining and the CLP(FD) finite domain library of SICStus. An alternate constraint solver based on Kodkod (and thus SAT) is also available within ProB, as is an integration with the SMT solver Z3. An alternate model checking engine (using TLC) well-suited for lower level B specifications is also available. The ProB Licence can be found here.


ProB covers a large part of B, and we are striving towards full coverage of Atelier B and B4Free constructs. ProB supports B features such as non-deterministic operations, ANY statements, operations with complex arguments, sets, sequences, functions, lambda abstractions, set comprehensions, records, constants and properties, and many more. Not supported are some of the Atelier B tree operations and there are restrictions on DEFINITIONS. ProB does support multiple machines, refinements, and implementations. ProB can also be used for automated refinement checking and LTL model checking. It also supports almost full CSP-M process descriptions, to be used on their own or to guide B machines for specification and property validation. The state space of the specifications can be graphically visualized. ProB also supports Z specifications (ProB in this context is sometimes called ProZ) as well as TLA+ specifications. We now also have an online ProB Logic Calculator.