The CADE ATP System Competition

Design and Organization

This document contains information about the:

The rules, specifications, and deadlines given here are absolute. Only the competition panel has the right to make exceptions.

Disclaimer

Every effort has been made to organize the competition in a fair and constructive manner. No responsibility is taken if, for one reason or the other, your system does not win.

The design and procedures of this CASC evolved from those of previous CASCs. Important changes for this CASC are:

Divisions

CASC is divided into divisions according to problem and system characteristics. There are five competition divisions in which systems are explicitly ranked, and one demonstration division in which systems demonstrate their abilities without being formally ranked. Entry into the competition divisions is subject to the following rules:

Competition Divisions

The Problems section explains what problems are eligible for use in each division and category.

Demonstration Division

ATP systems that cannot run on the general hardware, or cannot be entered into the competition divisions for any other reason, can be entered into the demonstration division. Demonstration division systems can run on the general hardware, or the hardware can be supplied by the entrant. Hardware supplied by the entrant may be brought to CASC, or may be accessed via the internet.

The entry specifies which competition divisions' problems are to be used. The results are presented along with the competition divisions' results, but may not be comparable with those results.

Infrastructure

Hardware and Software

The general hardware is Dell Precision 330 workstations, each having:

Problems

Problem Selection
The problems are from the TPTP Problem Library, version v2.5.0. The TPTP version used for the competition is not released until after the system installation deadline.

Warning: There are some very large problems in TPTP v2.5.0, e.g., this one (with the header mostly removed to maintain anonymity).

The problems have to meet certain criteria to be eligible for selection:

The problems used are randomly selected from the eligible problems at the start of the competition, based on a seed supplied by the competition panel. The selection has constraints:

Number of Problems
The minimal numbers of problems that have to be used in each division and category, to ensure sufficient confidence in the competition results, are determined from the numbers of eligible problems in each division and category (the competition organizers have to ensure that there is sufficient CPU time available to run the ATP systems on this minimal number of problems). The minimal numbers of problems is used in determining the CPU time limit imposed on each solution attempt.

A lower bound on the total number of problems that is used is determined from the number of workstations available, the time allocated to the competition, the number of ATP systems to be run on the general hardware over all the divisions, and the CPU time limit, according to the following relationship: 

                     Number of workstations * Time allocated
Number of problems = ---------------------------------------
                      Number of ATP systems * CPU time limit
It is a lower bound on the total number of problems because it assumes that every system uses all of the CPU time limit for each problem. Since some solution attempts succeed before the CPU time limit is reached, more problems can be used. The numbers of problems used in each division and category are determined according to the judgement of the competition organizers.

Problem Preparation
It is necessary to ensure that no system receives an advantage or disadvantage due to the specific presentation of the problems in the TPTP. To this end the tptp2X utility, distributed with the TPTP, is used to:

Further, to prevent systems from recognizing problems from their file names, symbolic links are made to the selected problems, using names of the form CCCNNN-1.p for the symbolic links, with NNN running from 001 to the number of problems in the respective division or category. The problems are specified to the ATP systems using the symbolic link names.

In the demonstration division the same problems are used as for the competition divisions, with the same tptp2X transformations applied. However, the original file names are retained.

Time Limits

In the competition divisions, CPU and wall clock time limits are imposed on each solution attempt. A minimal CPU time limit of 180 seconds is used. The maximal CPU time limit is determined using the relationship used for determining the number of problems, with the minimal number of problems as the "Number of problems". The CPU time limit is chosen as a reasonable value within the range allowed, and is announced at the competition. The wall clock time limit is imposed in addition to the CPU time limit, to prevent very high memory usage that causes swapping. The wall clock time limit is double the CPU time limit.

In the demonstration division, each entrant can choose to use either a CPU or a wall clock time limit, whose value is the CPU time limit of the competition divisions.

Performance Evaluation

At some time before the competition, all systems running in the competition divisions are tested for soundness. Non-theorems (satisfiable variants of the eligible problems, e.g., without the conjecture clause, and satisfiable problems selected from the TPTP) are submitted to the systems in the MIX, UEQ, FOF, and EPR divisions, and theorems (selected from the TPTP) are submitted to the systems in the SAT and EPR divisions. Finding a proof of a non-theorem or a disproof of a theorem indicates unsoundness. If an ATP system fails the soundness testing it must be repaired or is disqualified. The soundness testing has a secondary aim of eliminating the possibility of an ATP system simply delaying for some amount of time and then claiming to have found a solution. In the demonstration division no soundness testing has to be performed.

During the competition, for each ATP system, for each problem attempted, three items of data are recorded: whether or not a solution was found, the CPU time taken, and whether or not a solution (proof or model) was output. In the MIX division proof class, the systems are ranked according to the number of problems solved with a proof output. In the MIX division assurance class and all other divisions, the systems are ranked according to the numbers of problems solved. If there is a tie according to these rankings, then the tied systems are ranked according to their average CPU times over problems solved. If any division is won by the system that won that division in the previous CASC, then no winner is be announced in that division. Otherwise winners are announced in each division (two class winners in the MIX division), and prizes are awarded.

At some time after the competition, all high ranking systems in each division are tested over the entire TPTP. This provides a final check for soundness. If a system is found to be unsound, and it cannot be shown that the unsoundness did not manifest itself in the competition, then the system is retrospectively disqualified. At some time after the competition, the proofs from the winner of the MIX division proof class are checked by the panel. If any of the proofs are unacceptable, i.e., they are significantly worse than the samples provided, then that system is retrospectively disqualified from the proof class. In all cases, the unsoundness will be reported in the journal paper about the competition.

Entry Requirements and Procedures

To be entered into CASC, systems have to be registered using the CASC system registration form. No registrations are accepted after the registration deadline. For each system entered, a person has to be nominated to handle all issues (including execution difficulties) arising before and during the competition. The nominated entrant must formally register for CASC. However, it is not necessary for entrants to physically attend the competition.

Entering many similar versions of the same system is deprecated. Entrants may be required to limit the number of system versions that they enter. The division winners from the previous CASC are automatically entered into their divisions, to provide benchmarks against which progress can be judged. Systems entered in the MIX division are automatically ranked in the assurance class, and are ranked in the proof class if they output acceptable proofs. After the competition all systems' source code is made publically available on the CASC WWW site.

It is assumed that each entrant has read the WWW pages related to the competition, and has complied with the competition rules. Non-compliance with the rules could lead to disqualification. A "catch-all" rule is used to deal with any unforseen circumstances: No cheating is allowed. The panel is allowed to disqualify entrants due to unfairness, and to adjust the competition rules in case of misuse.

System Description and Proof Objects

A system description has to be provided for each ATP system entered, using this HTML schema. The system description must fit onto two pages, using 12pt times font. The schema has the following sections: The system description has to be emailed to the competition organizers before the system description deadline. The system descriptions, along with information regarding the competition design and procedures, form the proceedings for the competition.

For systems in the MIX division proof class, representative sample proofs must be emailed to the competition organizers before the sample solutions deadline. The sample proofs must illustrate the use of all inference rules. A key must be provided if any non-obvious abbreviations for inference rules or other information are used. The competition panel decides whether or not the proof objects are acceptable.

System Properties

The precomputation and storage of any information specifically about TPTP problems is not allowed. Strategies and strategy selection based on the characteristics of a few specific TPTP problems is not allowed, i.e., strategies and strategy selection must be general purpose and expected to extend usefully to new unseen problems. If automatic strategy learning procedures are used, the learning must ensure that sufficient generalization is obtained, and that no learning at the individual problem level is performed.

For every problem solved, the system's solution process has to be reproducible by running the system again.

With the exception of the MIX division proof class, the ATP systems are not required to output solutions (proofs or models). However, systems that do output solutions to stdout are highlighted in the presentation of results.

System Installation

Access to the general hardware (or equivalent) is available from the general hardware access deadline. Entrants must install their systems on the general hardware, and ensure that their systems execute in the competition environment, according to the checks listed below. Entrants are advised to perform these checks well in advance of the system installation deadline. This gives the competition organizers time to help resolve any difficulties encountered.

The ATP systems have to be executable by a single command line, using an absolute path to the executable that may not be in the current directory. The command line arguments are the absolute path name for a symbolic link as the problem file name, the time limit (if required by the entrant), and entrant specified system switches (the same for all problems). No shell features, such as input or output redirection, may be used in the command line. No assumptions may be made about the format of the problem file name.

The ATP systems that run on the general hardware have to be interruptable by a SIGXCPU signal, so that the CPU time limit can be imposed on each solution attempt, and interruptable by a SIGALRM signal, so that the wall clock time limit can be imposed on each solution attempt. For systems that create multiple processes, the signal is sent first to the process at the top of the hierarchy, then one second later to all processes in the hierarchy. Any orphan processes are killed after that, using SIGKILL. The default action on receiving these signals is to exit (thus complying with the time limit, as required), but systems may catch the signals and exit of their own accord. Both approaches are acceptable for the competition. If a system runs past a time limit this is noticed in the timing data, and the system is considered to have not solved that problem. When terminating of their own accord, the ATP systems have to output a distinguished string (specified by the entrant) to stdout indicating the result, one of: When outputing proofs for MIX division's proof class, the start and end of the proof must be identified by distinguished strings (specified by the entrant). If an ATP system terminates of its own accord, it may not leave any temporary or other output files. If an ATP system is terminated by a SIGXCPU or SIGALRM, it may not leave any temporary or other output files anywhere other than in /tmp.

Multiple copies of the ATP systems have to be executable concurrently on different machines but in the same (NFS cross mounted) directory. It is therefore necessary to avoid producing temporary files that do not have unique names, with respect to the machines and other processes. An adequate solution is a file name including the host machine name and the process id.

For practical reasons excessive output from the ATP systems is not allowed. A limit, dependent on the disk space available, is imposed on the amount of stdout and stderr output that can be produced. The limit is at least 10KB per problem (averaged over all problems so that it is possible to produce some long proofs).

System Delivery

For systems running on the general hardware, entrants have to deliver an installation package to the competition organizers by the installation deadline. The installation package must be a .tar.gz file containing the system source code, any other files required for installation, and a ReadMe file. The ReadMe file must contain instructions for installation, instructions for executing the system, and the distinguished strings output to indicate the result.

The installation procedure may require changing path variables, invoking make or something similar, etc, but nothing unreasonably complicated. All system binaries must be created in the installation process; they cannot be delivered as part of the installation package. The system is reinstalled onto the general hardware by the competition organizers, following the instructions in the ReadMe file. Installation failures before the installation deadline are passed back to the entrant. After the installation deadline access to the general hardware is denied, and no further changes or late systems are accepted (i.e., deliver your installation package before the installation deadline so if the installation fails you have a chance to fix it!). If you are in doubt about your installation package or procedure, please email the competition organizers.

For systems running on entrant suuplied hardware in the demonstration division the systems are installed on the respective hardware by the entrants.

System Execution

Execution of the ATP systems on the general hardware is controlled by a perl script, provided by the competition organizers. The jobs are queued onto the workstations so that each workstation is running one job at a time. All attempts at the Nth problems in all the divisions and categories are started before any attempts at the (N+1)th problems.

During the competition a perl script parses the systems' outputs. If any of an ATP system's distinguished strings are found then the CPU time used to that point is noted. A system has solved a problem iff it outputs its "success" string within the CPU time limit, and a system has produced a proof iff it outputs its "end of proof" string within the CPU time limit. The result and timing data is used to generate an HTML file, and a WWW browser is used to display the results.

The execution of the demonstration division systems is supervised by their entrants.