MaLeS: A Framework for Automatic Tuning of Automated Theorem Provers

MaLeS is an automatic tuning framework for automated theorem provers. It provides solutions for both the strategy finding as well as the strategy scheduling problem. This paper describes the tool and the methods used in it, and evaluates its performance on three automated theorem provers: E, LEO-II and Satallax. An evaluation on a subset of the TPTP library problems shows that on average a MaLeS-tuned prover solves 8.67% more problems than the prover with its default settings

TOOLympics 2019: An Overview of Competitions in Formal Methods

Evaluation of scientific contributions can be done in many different ways. For the various research communities working on the verification of systems (software, hardware, or the underlying involved mechanisms), it is important to bring together the community and to compare the state of the art, in order to identify progress of and new challenges in the research area. Competitions are a suitable way to do that. The first verification competition was created in 1992 (SAT competition), shortly followed by the CASC competition in 1996. Since the year 2000, the number of dedicated verification competitions is steadily increasing. Many of these events now happen regularly, gathering researchers that would like to understand how well their research prototypes work in practice. Scientific results have to be reproducible, and powerful computers are becoming cheaper and cheaper, thus, these competitions are becoming an important means for advancing research in verification technology. TOOLympics 2019 is an event to celebrate the achievements of the various competitions, and to understand their commonalities and differences. This volume is dedicated to the presentation of the 16 competitions that joined TOOLympics as part of the celebration of the 25th anniversary of the TACAS conference

Result Certification of Static Program Analysers with Automated Theorem Provers

International audienceThe automation of the deductive approach to program veri- fication crucially depends on the ability to efficiently infer and discharge program invariants. In an ideal world, user-provided invariants would be strengthened by incorporating the result of static analysers as untrusted annotations and discharged by automated theorem provers. However, the results of object-oriented analyses are heavily quantified and cannot be discharged, within reasonable time limits, by state-of-the-art auto- mated theorem provers. In the present work, we investigate an original approach for verifying automatically and efficiently the result of certain classes of object-oriented static analyses using off-the-shelf automated theorem provers. We propose to generate verification conditions that are generic enough to capture, not a single, but a family of analyses which encompasses Java bytecode verification and Fähndrich and Leino type- system for checking null pointers. For those analyses, we show how to generate tractable verification conditions that are still quantified but fall in a decidable logic fragment that is reducible to the Effectively Propositional logic. Our experiments confirm that such verification conditions are efficiently discharged by off-the-shelf automated theorem provers

Automated Deduction – CADE 28

This open access book constitutes the proceeding of the 28th International Conference on Automated Deduction, CADE 28, held virtually in July 2021. The 29 full papers and 7 system descriptions presented together with 2 invited papers were carefully reviewed and selected from 76 submissions. CADE is the major forum for the presentation of research in all aspects of automated deduction, including foundations, applications, implementations, and practical experience. The papers are organized in the following topics: Logical foundations; theory and principles; implementation and application; ATP and AI; and system descriptions

Reasoning in the OWL 2 Full Ontology Language using First-Order Automated Theorem Proving

OWL 2 has been standardized by the World Wide Web Consortium (W3C) as a family of ontology languages for the Semantic Web. The most expressive of these languages is OWL 2 Full, but to date no reasoner has been implemented for this language. Consistency and entailment checking are known to be undecidable for OWL 2 Full. We have translated a large fragment of the OWL 2 Full semantics into first-order logic, and used automated theorem proving systems to do reasoning based on this theory. The results are promising, and indicate that this approach can be applied in practice for effective OWL reasoning, beyond the capabilities of current Semantic Web reasoners. This is an extended version of a paper with the same title that has been published at CADE 2011, LNAI 6803, pp. 446-460. The extended version provides appendices with additional resources that were used in the reported evaluation

Efficient reasoning procedures for complex first-order theories

The complexity of a set of first-order formulas results from the size of the set and the complexity of the problem described by its formulas. Decision Procedures for Ontologies This thesis presents new superposition based decision procedures for large sets of formulas. The sets of formulas may contain expressive constructs like transitivity and equality. The procedures decide the consistency of knowledge bases, called ontologies, that consist of several million formulas and answer complex queries with respect to these ontologies. They are the first superposition based reasoning procedures for ontologies that are at the same time efficient, sound, and complete. The procedures are evaluated using the well-known ontologies YAGO, SUMO and CYC. The results of the experiments, which are presented in this thesis, show that these procedures decide the consistency of all three above-mentioned ontologies and usually answer queries within a few seconds. Reductions for General Automated Theorem Proving Sophisticated reductions are important in order to obtain efficient reasoning procedures for complex, particularly undecidable problems because they restrict the search space of theorem proving procedures. In this thesis, I have developed a new powerful reduction rule. This rule enables superposition based reasoning procedures to find proofs in sets of complex formulas. In addition, it increases the number of problems for which superposition is a decision procedure.Die Komplexität einer Formelmenge für einen automatischen Theorembeweiser in Prädikatenlogik 1. Stufe ergibt sich aus der Anzahl der zu betrachtenden Formeln und aus der Komplexität des durch die Formeln beschriebenen Problems. Entscheidungsprozeduren für Ontologien Diese Arbeit entwickelt effiziente auf Superposition basierende Beweisprozeduren für sehr große entscheidbare Formelmengen, die ausdrucksstarke Konstrukte, wie Transitivität und Gleichheit, enthalten. Die Prozeduren ermöglichen es Wissenssammlungen, sogenannte Ontologien, die aus mehreren Millionen Formeln bestehen, auf Konsistenz hin zu überprüfen und Antworten auf komplizierte Anfragen zu berechnen. Diese Prozeduren sind die ersten auf Superposition basierten Beweisprozeduren für große, ausdrucksstarke Ontologien, die sowohl korrekt und vollständig, als auch effizient sind. Die entwickelten Prozeduren werden anhand der weit bekannten Ontologien YAGO, SUMO und CYC evaluiert. Die Experimente zeigen, dass diese Prozeduren die Konsistenz aller untersuchten Ontologien entscheiden und Anfragen in wenigen Sekunden beantworten. Reduktionen für allgemeines Theorembeweisen Um effiziente Prozeduren für das Beweisen in sehr schwierigen und insbesondere in unentscheidbaren Formelmengen zu erhalten, sind starke Reduktionsregeln, die den Beweisraum einschränken, von essentieller Bedeutung. Diese Arbeit entwickelt eine neue mächtige Reduktionsregel, die es Superposition ermöglicht Beweise in sehr schwierigen Formelmengen zu finden und erweitert die Menge von Problemen, für die Superposition eine Entscheidungsprozedur ist

Mechanised Uniform Interpolation for Modal Logics K, GL, and iSL

The uniform interpolation property in a given logic can be understood as the definability of propositional quantifiers. We mechanise the computation of these quantifiers and prove correctness in the Coq proof assistant for three modal logics, namely: (1) the modal logic K, for which a pen-and-paper proof exists; (2) Gödel-Löb logic GL, for which our formalisation clarifies an important point in an existing, but incomplete, sequent-style proof; and (3) intuitionistic strong Löb logic iSL, for which this is the first proof-theoretic construction of uniform interpolants. Our work also yields verified programs that allow one to compute the propositional quantifiers on any formula in this logic