The International Satisfiability Modulo Theories (SMT) Competition.


Benchmark Submission
Previous Editions


Proof Exhibition Track
Parallel & Cloud Tracks

Proof Exhibition Track

In the new Proof Exhibition Track, teams can submit a proof-producing solver together with a proof checker for its proof format. We will compile and present the results, as well as assemble a panel of experts (not necessarily organizers) to do a qualitative assessment for each proof-producing solver, proof format, and proof checker.

Solver Script for StarExec

Solver authors should provide two scripts with their solver. The first script called smtcomp_solver, should take the name of the benchmark file as a single argument and run the solver on the benchmark.

As usual the benchmark is pre-processed, i.e., the identifiers are randomized and the commands for producing proofs are added to the benchmark. The solver needs to understand the option :produce-proofs and the command (get-proof). Solvers must respond to each command in the benchmark script with the answer defined in the SMT-LIB format specification. There will be a (check-sat) command for which unsat should be output and a (get-proof) command for which the proof should be given as an s-expression according to the SMT-LIB standard (the format is not specified otherwise). Solvers that respond unknown to the (check-sat) command should respond with an error to the following (get-proof) command. Note that the error result must be output to stdout. In contrast to other tracks, anything written to stderr is ignored and the output is saved for diagnostic purposes.

Proof Checker Script for StarExec

The second script, smtcomp_checker, should take the benchmark file name as first argument and the stdout output of the solver script as second argument. Note that this output will usually start with the unsat result of the (check-sat) command, which the checker must either parse or skip.

The checker should check the proof within the output and provide the result to stdout. Output printed to stderr is ignored (and saved for diagnostics). The first line of the proof checker result should be either valid, invalid, holey, sat, or unknown. The answer valid must only be given when the checker certifies that the given proof justifies the unsatisfiability of the given benchmark. A checker that returns valid to a satisfiable benchmark is deemed to be unsound. The answer invalid should be returned if the proof is errorneous or otherwise malformed. If the proof checker determines that the proof is valid but it contains holes, i.e., steps that are not checked for correctness, the answer should be holey. The answer sat should be given if the solver claimed that the benchmark is satisfiable and unknown should be given if (1) the solver answered unknown, (2) it answered unsat but did not give a proof, or (3) the solver gave an error result.

After the first line, the proof checker can provide arbitrary key=value pairs. These will be collected in the final result table and can include for example information about the number of proof steps, the number of nodes in the proof, the number of holes, the number of different proof rules, etc.

Evaluating the Results

The result of a solver is considered erroneous if the proof checker returns sat or invalid. Since the proof exhibition track is non-competitive and we are not fixing the definition of a valid proof, there will be no score computed for this track.

A proof checker is unsound if it returns valid for an (invalid) proof of a satisfiable benchmark. Thus, a proof checker must also check that the formula that was proved corresponds to the benchmark given. Soundness of the proof checker is a central criterion by which the participants will be judged.

Time Limit.

This track will use a wall-clock time limit of 20 minutes per solver/benchmark pair. This time limit includes the time for proof checking. We will record the times for each stage.


Solvers in this track will be wrapped in the competition to include the script starexec_run_proof. This script will call the solver and checker script.

If you participate in the proof track, you should include the script mentioned above in your solver binary. You can submit a single solver binary for all tracks, by providing a starexec_run_default script for the other tracks. You also need to create smtcomp_solver and smtcomp_checker scripts for the proof exhibition track. You can also create more configurations for the other tracks by adding a corresponding starexec_run_track script

Key-Value Pairs

As mentioned above the proof checker can add arbitrary key-value pairs that will be collected in the results. To standardize the results, we will at a later time propose some key-value pairs, that proof checkers should print. Please check this page for updates.