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The two-volume set LNCS 15529 and 15530 constitutes the proceedings of the 26th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2025, held in Denver, CO, USA, during January 20–21, 2025.The 20 full papers together with 2 accepted tool papers and 18 full length regular and case-study papers presented in the proceedings were carefully reviewed and selected from 48 submissions. The program of VMCAI 2025 conference in the core areas of VMCAI including abstract interpretation, programming languages, hardware and software model checking, cyber-physical systems, formal synthesis, formal methods in artificial intelligence, concurrency and other areas.

The two-volume set LNCS 15529 and 15530 constitutes the proceedings of the 26th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2025, held in Denver, CO, USA, during January 20–21, 2025.The 20 full papers together with 2 accepted tool papers and 18 full length regular and case-study papers presented in the proceedings were carefully reviewed and selected from 48 submissions. The program of VMCAI 2025 conference in the core areas of VMCAI including abstract interpretation, programming languages, hardware and software model checking, cyber-physical systems, formal synthesis, formal methods in artificial intelligence, concurrency and other areas.

This book constitutes the refereed proceedings of the 15th International Conference on Verified Software, VSTTE 2023, held in Ames, IA, USA, October 23–24, 2023. The 6 full papers presented in this volume were carefully reviewed and selected from 13 submissions. They focus on requirements modeling, specification languages, software design methods, automatic code generation, refinement methodologies, and more.

This book constitutes the revised selected papers of the 5th International Workshop on Dynamic Logic. New Trends and Applications, DaLí 2023, held in Tbilisi, Georgia, during September 15–16, 2023. The 8 full papers in this book were carefully reviewed and selected from 10 submissions. They deal with new trends and applications in the area of Dynamic Logic.

This book constitutes the proceedings of the 6th International Workshop on Formal Methods Teaching, FMTea 2024, which was held in Milan, Italy, on September 10, 2024. The 7 full papers included in these proceedings were carefully reviewed and selected from 9 submissions. The book also contains one invited talk in full paper length. The papers focus on learning formal methods for the purpose of teaching and self-learning.

This book constitutes the refereed proceedings of the 27th Brazilian Symposium on Formal Methods: Foundations and Applications, SBMF 2024, held in Vitória, Brazil, during December 4–6, 2024. The 8 full papers and 4 short papers included in this book were carefully reviewed and selected from 18 submissions. They were organized in topical sections as follows: Formal Analysis and Verification in Temporal and Symbolic Systems; Formal Semantics and Verification of UML Models; Formal Verification and Proof Techniques in Algorithms and Logics; and Formal Methods for Security and Privacy.

This book constitutes the proceedings of the 18th International Conference on Reachability Problems, RP 2024, which took place in Vienna, Austria, during September 25–27, 2024. The 13 full papers included in these proceedings were carefully reviewed and selected from 37 submissions. The book also contains two invited talks in full paper length. The contributions in these proceedings cover topics from computability and reachability; automata and complexity; linear systems and recurrences; and games and abstractions.

The two-volume set LNCS 14499 and 14500 constitutes the proceedings of the 25th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2024, which took place in London, Ontario, Canada, in January 2024. The 30 full papers presented in the proceedings were carefully reviewed and selected from 74 submissions. They were organized in topical sections as follows:Part I: Abstract interpretation; infinite-state systems; model checking and synthesis; SAT, SMT, and automated reasoning; Part II: Concurrency; neural networks; probabilistic and quantum programs; program and system verification; runtime verification; security and privacy.

The two-volume set LNCS 14499 and 14500 constitutes the proceedings of the 25th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2024, which took place in London, Ontario, Canada, in January 2024. The 30 full papers presented in the proceedings were carefully reviewed and selected from 74 submissions. They were organized in topical sections as follows:Part I: Abstract interpretation; infinite-state systems; model checking and synthesis; SAT, SMT, and automated reasoning; Part II: Concurrency; neural networks; probabilistic and quantum programs; program and system verification; runtime verification; security and privacy;

This book constitutes the refereed proceedings of the 26th Brazilian Symposium on Formal Methods, SBMF 2023, held in Manaus, Brazil, during December 4-8, 2023.The 7 full papers and 2 short papers presented in this book were carefully reviewed and selected from 16 submissions.The papers are divided into the following topical sections: specification and modeling languages; testing; and verification and validation.

This book constitutes revised selected papers from the refereed proceedings of the 4th International Workshop on Dynamic Logic, DaLí 2022, held in Haifa, Israel, in July/August 2022.The 8 full papers presented in this volume were carefully reviewed and selected from 22 submissions. They deal with new trends and applications in the area of Dynamic Logic.

This book constitutes the proceedings of the 24th International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2023, which took place in Boston, USA, in January 2023. The 17 full papers presented in this book were carefully reviewed and selected from 34 submissions. The contributions deal with program verification, model checking, abstract interpretation, program synthesis, static analysis, type systems, deductive methods, decision procedures, theorem proving, program certification, debugging techniques, program transformation, optimization, and hybrid and cyber-physical systems.

This book constitutes the refereed proceedings of the 21st International Conference on Software Engineering and Formal Methods, SEFM 2023, held in Eindhoven, The Netherlands, during November 6-10, 2023. The 18 regular papers presented in this book, together with 1 invited paper and 1 tool paper, were carefully reviewed and selected from 41 submissions. The SEFM conference series aims to bring together researchers and practitioners from academia, industry and government, to advance the state of the art in formal methods, to facilitate their uptake in the software industry, and to encourage their integration within practical software engineering methods and tools.

This book constitutes the refereed proceedings of the 14th International Conference on Verified Software. Theories, Tools and Experiments, VSTTE 2022 held in Trento, Italy, during October 17–18, 2022.The 9 papers presented in this volume were carefully reviewed and selected from 20 submissions. The papers describe software verification efforts that involve collaboration, theory unification, tool integration, and formalized domain knowledge as well as novel experiments and case studies evaluating verification techniques and technologies.

This book constitutes the refereed proceedings of the 17th International Conference on Reachability Problems, RP 2023, held in Nice, France, during October 11–13, 2023.The 13 full papers included in this book were carefully reviewed and selected from 19 submissions. They present recent research on reachability problems to promote the exploration of new approaches for the modeling and analysis of computational processes by combining mathematical, algorithmic, and computational techniques.

Edited in collaboration with FoLLI, this book constitutes the refereed proceedings of the 10th Indian Conference on Logic and Its Applications, ICLA 2023, which was held in Indore, India, in March 2023.Besides 6 invited papers presented in this volume, there are 9 contributed full papers which were carefully reviewed and selected from 18 submissions. The volume covers a wide range of topics. These topics are related to modal and temporal logics, intuitionistic connexive and imperative logics, systems for reasoning with vagueness and rough concepts, topological quasi-Boolean logic and quasi-Boolean based rough set models, and first-order definability of path functions of graphs.

This book constitutes the proceedings of the 26th International Conference on Implementation and Application of Automata, CIAA 2022, held in Rouen, France in June/ July 2022. The 16 regular papers presented together with 3 invited lectures in this book were carefully reviewed and selected from 26 submissions. The topics of the papers covering various fields in the application, implementation, and theory of automata and related structures.

This book constitutes the refereed proceedings of the 15th International Conference on Reachability Problems, RP 2022, held in Kaiserslautern, Germany, in October 2022.The 8 full papers presented were carefully reviewed and selected from 14 submissions. In addition, 3 invited papers were included in this volume. The RP proceedings cover topics such as reachability for infinite state systems; rewriting systems; reachability analysis in counter/timed/cellular/communicating automata; Petri nets; computational aspects of semigroups, groups, and rings; reachability in dynamical and hybrid systems; frontiers between decidable and undecidable reachability problems; complexity and decidability aspects; predictability in iterative maps; and new computational paradigms.

This book constitutes the refereed proceedings of the 20th International Conference on Software Engineering and Formal Methods, SEFM 2022, which took place in Berlin, Germany, in September 2022. The 19 full and 3 short papers included in this book were carefully reviewed and selected from 62 submissions. They were organized in topical sections as follows: software verification; program analysis; verifier technology; formal methods for intelligent and learning systems; specification and contracts; program synthesis; temporal logic; and runtime methods.

This book constitutes the refereed proceedings of the 25th Brazilian Symposium on Formal Methods, SBMF 2022, which was held virtually in December 2022. The 8 regular papers presented in this book were carefully reviewed and selected from 15 submissions. The symposium focuses on the development, dissemination, and use of formal methods for the construction of high-quality computational systems, aiming to promote opportunities for researchers and practitioners with an interest in formal methods to discuss the recent advances in this area.

This book constitutes the refereed proceedings of the 20th International Conference on Formal Modeling and Analysis of Timed Systems, FORMATS 2022, held in Warsaw, Poland, in September 2022. The 12 full papers together with 2 short papers that were carefully reviewed and selected from 30 submissions are presented in this volume with 3 full-length papers associated with invited/anniversary talks. The papers focus on topics such as modelling, design and analysis of timed computational systems. The conference aims in real-time issues in hardware design, performance analysis, real-time software, scheduling, semantics and verification of real-timed, hybrid and probabilistic systems.

This book constitutes the refereed proceedings of the 13th International Tbilisi Symposium on Logic, Language and Computation, TbiLLC 2019, held in Batumi, Georgia, in September 2019. The volume contains 17 full revised papers presented at the conference from 17 submissions. The scientific program consisted of tutorials, invited lectures, contributed talks, and two workshops. The symposium offered two tutorials in language and logic and aimed at students as well as researchers working in the other areas: · Language: Sign language linguistics. State of the art, by Fabian Bross (University of Stuttgart, Germany) · Logic: Axiomatic Semantics, by Graham E. Leigh (University of Gothenburg, Sweden)

This Festschrift, dedicated to Frits W. Vaandrager on the occasion of his 60th birthday, contains papers written by many of his closest collaborators. Frits has been a Professor of Informatics for Technical Applications at Radboud University Nijmegen since 1995, where his research focuses on formal methods, concurrency theory, verification, model checking, and automata learning. The volume contains contributions of colleagues, Ph.D. students, and researchers with whom Frits has collaborated and inspired, reflecting a wide spectrum of scientific interests, and demonstrating successful work at the highest levels of both theory and practice.

This book constitutes the proceedings of the 24th International Conference on Theory and Applications of Satisfiability Testing, SAT 2021, which took place in Barcelona, Spain, in July 2021.The 37 full papers presented in this volume were carefully reviewed and selected from 73 submissions. They deal with theory and applications of the propositional satisfiability problem, broadly construed. Aside from plain propositional satisfiability, the scope of the meeting includes Boolean optimization, including MaxSAT and pseudo-Boolean (PB) constraints, quantified Boolean formulas (QBF), satisfiability modulo theories (SMT), and constraint programming (CP) for problems with clear connections to Boolean reasoning.

This book constitutes the proceedings of the 22nd International Conference on Formal Engineering Methods, ICFEM 2020, held in Singapore, Singapore, in March 2021. The 16 full and 4 short papers presented together with 1 doctoral symposium paper in this volume were carefully reviewed and selected from 41 submissions. The papers cover theory and applications in formal engineering methods together with case studies. They also represent the recent development in the use and development of formal engineering methods for software and system development.

This book constitutes the proceedings of the 23rd International Conference on Theory and Applications of Satisfiability Testing, SAT 2020, which was planned to take place in Alghero, Italy, during July 5-9, 2020. Due to the coronavirus COVID-19 pandemic, the conference was held virtually. The 25 full, 9 short, and 2 tool papers presented in this volume were carefully reviewed and selected from 69 submissions. They deal with SAT interpreted in a broad sense, including theoretical advances (such as exact algorithms, proof complexity, and other complexity issues), practical search algorithms, knowledge compilation, implementation-level details of SAT solvers and SAT-based systems, problem encodings and reformulations, applications (including both novel application domains and improvements to existing approaches), as well as case studies and reports on findings based on rigorous experimentation.

The LNCS journal Transactions on Rough Sets is devoted to the entire spectrum of rough sets related issues, from logical and mathematical foundations, through all aspects of rough set theory and its applications, such as data mining, knowledge discovery, and intelligent information processing, to relations between rough sets and other approaches to uncertainty, vagueness, and incompleteness, such as fuzzy sets and theory of evidence. Volume XXII in the series is a continuation of a number of research streams that have grown out of the seminal work of Zdzislaw Pawlak during the first decade of the 21st century.

This book constitutes the refereed proceedings of the 11th International Symposium on Foundations of Information and Knowledge Systems, FoIKS 2020, held in Dortmund, Germany, in February 2020.The 19 revised full papers presented were carefully reviewed and selected from 33 submissions. The papers address various topics such as big data; database design; dynamics of information; information fusion; integrity and constraint management; intelligent agents; knowledge discovery and information retrieval; knowledge representation, reasoning and planning; logics in databases and AI; mathematical foundations; security in information and knowledge systems; semi-structured data and XML; social computing; the semantic web and knowledge management; and the world wide web.​

This book constitutes the proceedings of the 21st International Conference on Verification, Model Checking, and Abstract Interpretation, VMCAI 2020. The 21 papers presented in this volume were carefully reviewed from 44 submissions. VMCAI provides a forum for researchers from the communities of verification, model checking, and abstract Interpretation, facilitating interaction, cross-fertilization, and advancement of hybrid methods that combine these and related areas.

Edited in collaboration with FoLLI, the Association of Logic, Language and Information this book constitutes the refereed proceedings of the Second Interdisciplinary Workshop on Logic, Language, and Meaning, TLLM 2020, held in Tsinghua, China, in December 2020. The 12 full papers together presented were fully reviewed and selected from 40 submissions.Due to COVID-19 the workshop will be held online.The workshop covers a wide range of topics where monotonicity is discussed in the context of logic, causality, belief revision, quantification, polarity, syntax, comparatives, and various semantic phenomena in particular languages.

This book constitutes the refereed proceedings of the 16th International Conference on Integrated Formal Methods, IFM 2019, held in Lugano, Switzerland, in November 2020. The 24 full papers and 2 short papers were carefully reviewed and selected from 63 submissions. The papers cover a broad spectrum of topics: Integrating Machine Learning and Formal Modelling; Modelling and Verification in B and Event-B; Program Analysis and Testing; Verification of Interactive Behaviour; Formal Verification; Static Analysis; Domain-Specific Approaches; and Algebraic Techniques.

This book constitutes the proceedings of the Second International Workshop on Dynamic Logic, DALI 2019, held in Porto, Portugal in October 2019. The workshop was held in Porto, Portugal, on October 9, 2019, as part of the Formal Methods Week which hosted the 3rd World Congress on Formal Methods. The 12 full papers presented together with 2 short papers were carefully reviewed and selected from 26 submissions. The workshop is based on the project DaLí – Dynamic logics for cyber-physical systems: towards contract based design.

This book constitutes the proceedings of the 6th International Symposium on Dependable Software Engineering, SETTA 2020, held in Guangzhou, China, in November 2020. The 10 full and 1 short paper included in this volume were carefully reviewed and selected from 20 submissions. They deal with latest research results and ideas on bridging the gap between formal methods and software engineering.

This book constitutes the proceedings of the International Joint Conference on Rules and Reasoning, RuleML+RR 2020, held in Oslo, Norway, during June-July 2020•. This is the 4th conference of a new series, joining the efforts of two existing conference series, namely “RuleML” (International Web Rule Symposium) and “RR” (Web Reasoning and Rule Systems).The 7 full research papers presented together with 6 short technical communications papers were carefully reviewed and selected from 30 submissions.•The conference was held virtually due to the COVID-19 pandemic.

This book constitutes the thoroughly refereed post-conference proceedings of the 8th International Conference on Fundamentals of Software Engineering, FSEN 2019, held in Tehran, Iran, in May 2019.The 14 full papers and 3 short papers presented in this volume were carefully reviewed and selected from 47 submissions. The topics of interest in FSEN span over all aspects of formal methods, especially those related to advancing the application of formal methods in the software industry and promoting their integration with practical engineering techniques. The papers are organized in topical sections on agent based systems, theorem proving, learning, verification, distributed algorithms, and program analysis.

This book constitutes the refereed proceedings of the 15th International Conference on Integrated Formal Methods, IFM 2019, held in Bergen, Norway, in December 2019.The 25 full papers and 3 short papers were carefully reviewed and selected from 95 submissions. The papers cover a broad spectrum of topics: from language design to verification and analysis techniques, to supporting tools and their integration into software engineering practice including both theoretical approaches and practical implementations. Also included are the extended abstracts of 6'journal-first'papers.

This book collects the refereed proceedings of the 8th Indian Conference on Logic and Its Applications, ICLA 2019, held in Delhi, India, in March 2019. The volume contains 13 full revised papers along with 6 invited talks presented at the conference. The aim of this conference series is to bring together researchers from a wide variety of fields in which formal logic plays a significant role. Areas of interest include mathematical and philosophical logic, computer science logic, foundations and philosophy of mathematics and the sciences, use of formal logic in areas of theoretical computer science and artificial intelligence, logic and linguistics, and the relationship between logic and other branches of knowledge. Of special interest are studies in systems of logic in the Indian tradition, and historical research on logic.

This book constitutes the refereed proceedings of the Third International Workshop and Tutorial, FMTea 2019, Held as Part of the Third World Congress on Formal Methods, FM 2019, Porto, Portugal, October 2019. The 14 full papers presented together with 3 abstract papers were carefully reviewed and selected from 22 submissions. The papers are organized in topical sections named: Tutorial lectures; Teaching Program Verification; Teaching Program Development; and Effective Teaching Techniques.

​​This Festschrift was published in honor of Catuscia Palamidessi on the occasion of her 60th birthday.It features 6 laudations, which are available in the front matter of the volume, and 25 papers by close collaborators and friends. The papers are organized in topical sections named: concurrency; logic and constraint programming; security and privacy; and models and puzzles.These contributions are a tribute to Catuscia Palamidessi's intellectual depth, vision, passion for science, and tenacity in solving technical problems. They also reflect the breadth and impact of her work. Her scientific interests include, in chronological order, principles of programming languages, concurrency theory, security, and privacy.

This book constitutes the proceedings of the 23rd International Conference on Developments in Language Theory, DLT 2019, held in Warsaw, Poland, in August 2019. The 20 full papers presented together with three invited talks were carefully reviewed and selected from 30 submissions. The papers cover the following topics and areas: combinatorial and algebraic properties of words and languages; grammars, acceptors and transducers for strings, trees, graphics, arrays; algebraic theories for automata and languages; codes; efficient text algorithms; symbolic dynamics; decision problems; relationships to complexity theory and logic; picture description and analysis, polyominoes and bidimensional patterns; cryptography; concurrency; celluar automata; bio-inspired computing; quantum computing.

This book constitutes the refereed proceedings of the 22nd International Conference on Theory and Applications of Satisfiability Testing, SAT 2019, held in Lisbon, Portugal, UK, in July 2019. The 19 revised full papers presented together with 7 short papers were carefully reviewed and selected from 64 submissions. The papers address different aspects of SAT interpreted in a broad sense, including (but not restricted to) theoretical advances (such as exact algorithms, proof complexity, and other complexity issues), practical search algorithms, knowledge compilation, implementation-level details of SAT solvers and SAT-based systems, problem encodings and reformulations, applications (including both novel application domains and improvements to existing approaches), as well as case studies and reports on findings based on rigorous experimentation.

Prolog for logic programming is one of the most intensively studied software languages in the 1980s. During the same period, the data-flow model for parallel computation attracted a lot of attention of researchers in computer science; hence, it was very natural that several approaches were tried toward combining the two and implementing logic programs in parallel machines with the data-flow architecture. These approaches, however, were rather indirect ones in the sense that they developed programs describing AND/OR-parallelism for deduction using a data-flow language and executed them in a data-flow computer, and yet did not devise a ‘direct'model for parallel execution (reasoning) of a logic program. This book discusses fuzzy logic inferencing for Pong; dislog; SEProlog; and provides direct graphical representations of first-order logic for inference.

This book constitutes the thoroughly refereed proceedings of the 21st International Symposium on Logic-Based Program Synthesis and Transformation, LOPSTR 2011, held in Odense, Denmark in July 2011. The 6 revised full papers presented together with 8 additional papers were carefully reviewed and selected from 28 submissions. Among the topics covered are specification, synthesis, verification, analysis, optimization, specialization, security, certification, applications and tools, program/model manipulation, and transformation techniques for any programming language paradigm.

Chapter 1 - Introduction to Logic Programming Chapter 2 - Prolog Chapter 3 - Negation as Failure and Stable Model Semantics Chapter 4 - Answer Set Programming and Abductive Logic Programming Chapter 5 - Constraint Logic Programming Chapter 6 - Linear Logic Chapter 7 - Introduction to Type Theory Chapter 8 - Simply Typed Lambda Calculus Chapter 9 - Type Polymorphism and Type System Chapter 10 - Algebraic Data Type and Calculus of Constructions Chapter 11 - Composite Data Type and Covariance and Contravariance (Computer Science) Chapter 12 - Liskov Substitution Principle and Effect System Chapter 13 - Nominative Type System and Structural Type System Chapter 14 - Option Type and POPLmark Challenge Chapter 15 - Recursive Data Type and Strong Typing

Program synthesis is a solution to the software crisis. If we had a program that develops correct programs from specifications, then program validation and maintenance would disappear from the software life-cycle, and one could focus on the more creative tasks of specification elaboration, validation, and maintenance, because replay of program development would be less costly. This monograph describes a novel approach to Inductive Logic Programming (ILP), which cross-fertilizes logic programming and machine learning. Aiming at the synthesis of recursive logic programs only, and this from incomplete information, we take a software engineering approach that is more appropriate than a pure artificial intelligence approach. This book is suitable as a secondary text for graduate level courses in software engineering and artificial intelligence, and as a reference for practitioners of program synthesis.

Chapter 1 - Introduction to Logic Programming Chapter 2 - Prolog Chapter 3 - Negation as Failure and Stable Model Semantics Chapter 4 - Answer Set Programming and Abductive Logic Programming Chapter 5 - Constraint Logic Programming Chapter 6 - Linear Logic Chapter 7 - Datalog Chapter 8 - SLD Resolution and Cut (Logic Programming)

Cooperating Heterogeneous Systems provides an in-depth introduction to the issues and techniques surrounding the integration and control of diverse and independent software components. Organizations increasingly rely upon diverse computer systems to perform a variety of knowledge-based tasks. This presents technical issues of interoperability and integration, as well as philosophical issues of how cooperation and interaction between computational entities is to be realized. Cooperating systems are systems that work together towards a common end. The concepts of cooperation must be realized in technically sound system architectures, having a uniform meta-layer between knowledge sources and the rest of the system. The layer consists of a family of interpreters, one for each knowledge source, and meta-knowledge. A system architecture to integrate and control diverse knowledge sources is presented. The architecture is based on the meta-level properties of the logic programming language Prolog. An implementation of the architecture is described, a Framework for Logic Programming Systems with Distributed Execution (FLiPSiDE). Knowledge-based systems play an important role in any up-to-date arsenal of decision support tools. The tremendous growth of computer communications infrastructure has made distributed computing a viable option, and often a necessity in geographically distributed organizations. It has become clear that to take knowledge-based systems to their next useful level, it is necessary to get independent knowledge-based systems to work together, much as we put together ad hoc work groups in our organizations to tackle complex problems. The book is for scientists and software engineers who have experience in knowledge-based systems and/or logic programming and seek a hands-on introduction to cooperating systems. Researchers investigating autonomous agents, distributed computation, and cooperating systems will find fresh ideas and new perspectives on well-established approaches to control, organization, and cooperation.

Formal systems that describe computations over syntactic structures occur frequently in computer science. Logic programming provides a natural framework for encoding and animating such systems. However, these systems often embody variable binding, a notion that must be treated carefully at a computational level. This book aims to show that a programming language based on a simply typed version of higher-order logic provides an elegant, declarative means for providing such a treatment. Three broad topics are covered in pursuit of this goal. First, a proof-theoretic framework that supports a general view of logic programming is identified. Second, an actual language called λProlog is developed by applying this view to higher-order logic. Finally, a methodology for programming with specifications is exposed by showing how several computations over formal objects such as logical formulas, functional programs, and λ-terms and π-calculus expressions can be encoded in λProlog.

This book celebratesthe 25th anniversaryof GULP—the Italian Associationfor LogicProgramming.Authored by Italian researchersat the leading edge of their?elds, it presents an up-to-date survey of a broad collection of topics in logic programming, making it a useful reference for both researchers and students. During its 25-year existence, GULP has organised a wide range of national and international activities, including both conferences and summer schools. It has been especially active in supporting and encouraging young researchers, by providing scholarships for GULP events and awarding distinguished disser- tions. WeintheinternationallogicprogrammingcommunitylookuponGULPwith a combination of envy, admiration and gratitude. We are pleased to attend its conferences and summer schools, where we can learn about scienti?c advances, catch up with old friends and meet young students. It is an honour for me to acknowledge our appreciation to GULP for its outstanding contributions to our?eld and to express our best wishes for its continuing prosperity in the future. March 2010 Robert Kowalski Imperial College London Preface On June 18, 1985, a group of pioneering researchers, including representatives from industry, national research labs, and academia, attended the constituent assembly of the Group of researchers and Users of Logic Programming (GULP) association. That was the starting point of a long adventure in science, that 1 we are still experiencing 25 years later. This volume celebrates this important event.