Static analysis of software with deductive methods is a highly dynamic field of research on the verge of becoming a mainstream technology in software engineering. It consists of a large portfolio of - mostly fully automated - analyses: formal verification, test generation, security analysis, visualization, and debugging. All of them are realized in the state-of-art deductive verification framework KeY. This book is the definitive guide to KeY that lets you explore the full potential of deductive software verification in practice. It contains the complete theory behind KeY for active researchers who want to understand it in depth or use it in their own work. But the book also features fully self-contained chapters on the Java Modeling Language and on Using KeY that require nothing else than familiarity with Java. All other chapters are accessible for graduate students (M.Sc. level and beyond). The KeY framework is free and open software, downloadable from the book companion website which contains also all code examples mentioned in this book.

This book presents reflections on the occasion of 20 years on the KeY project that focuses on deductive software verification. Since the inception of the KeY project two decades ago, the area of deductive verification has evolved considerably. Support for real world programming languages by deductive program verification tools has become prevalent. This required to overcome significant theoretical and technical challenges to support advanced software engineering and programming concepts. The community became more interconnected with a competitive, but friendly and supportive environment. We took the 20-year anniversary of KeY as an opportunity to invite researchers, inside and outside of the project, to contribute to a book capturing some state-of-the-art developments in the field. We received thirteen contributions from recognized experts of the field addressing the latest challenges. The topics of the contributions range from tool development, effciency and usability considerations to novel specification and verification methods. This book should offer the reader an up-to-date impression of the current state of art in deductive verification, and we hope, inspire her to contribute to the field and to join forces. We are looking forward to meeting you at the next conference, to listen to your research talks and the resulting fruitful discussions and collaborations.

The ultimate goal of program verification is not the theory behind the tools or the tools themselves, but the application of the theory and tools in the software engineering process. Our society relies on the correctness of a vast and growing amount of software. Improving the software engineering process is an important, long-term goal with many steps. Two of those steps are the KeY tool and this KeY book.

Software components and component-based software development (CBSD) are acknowledged as the best approach for constructing quality software at reasonable cost. Composing Software Components: A Software-testing Perspective describes a 10-year investigation into the underlying principles of CBSD. By restricting attention to the simplest cases, startling results are obtained: • Components are tested using only executable code. Their behavior is recorded and presented graphically. • Functional and non-functional behavior of systems synthesized from components are calculated from component tests alone. No access to components themselves is required. • Fast, accurate tools support every aspect of CBSD from design through debugging. Case studies of CBSD also illuminate software testing in general, particularly an expanded role for unit testing and the treatment of non-functional software properties. This unique book: • Contains more than a dozen case studies of fully worked-out component synthesis, with revealing insights into fundamental testing issues. • Presents an original, fundamental theory of component composition that includes persistent state and concurrency, based on functional software testing rather than proof-of-programs. • Comes with free supporting software with tutorial examples and data for replication of examples. The Perl software has been tested on Linux, Macintosh, and Windows platforms. Full documentation is provided. • Includes anecdotes and insights from the author’s 50-year career in computing as systems programmer, manager, researcher, and teacher. Composing Software Components: A Software-testing Perspective will help software researchers and practitioners to understand the underlying principles of component testing. Advanced students in computer science, engineering, and mathematics can also benefit from the book as a supplemental text and reference.

This book presents a collection of research papers that address the challenge of how to develop software in a principled way that, in particular, enables reasoning. The individual papers approach this challenge from various perspectives including programming languages, program verification, and the systematic variation of software. Topics covered include programming abstractions for concurrent and distributed software, specification and verification techniques for imperative programs, and development techniques for software product lines. With this book the editors and authors wish to acknowledge – on the occasion of his 60th birthday – the work of Arnd Poetzsch-Heffter, who has made major contributions to software technology throughout his career. It features articles on Arnd’s broad research interests including, among others, the implementation of programming languages, formal semantics, specification and verification of object-oriented and concurrent programs, programming language design, distributed systems, software modeling, and software product lines. All contributing authors are leading experts in programming languages and software engineering who have collaborated with Arnd in the course of his career. Overall, the book offers a collection of high-quality articles, presenting original research results, major case studies, and inspiring visions. Some of the work included here was presented at a symposium in honor of Arnd Poetzsch-Heffter, held in Kaiserslautern, Germany, in November 2018.

This book constitutes the refereed proceedings of the 13th International Conference on Verified Software, VSTTE 2021, and the 14th International Workshop on Numerical Software Verification, NSV 2021, held online, in July/ October 2021. Due to COVID-19 pandemic the conference was held virtually. There were 10 papers presented in this volume were carefully reviewed and selected from 20 submissions. The papers focuses on challenges of the verification of cyber-physical systems with machine learning components and making large-scale verified software a practical reality and much more.

The papers of this volume focus on the foundational aspects of computer science, the thematic origin and stronghold of LNCS, under the title “Computing and Software Science: State of the Art and Perspectives”. They are organized in two parts: The first part, Computation and Complexity, presents a collection of expository papers on fashionable themes in algorithmics, optimization, and complexity. The second part, Methods, Languages and Tools for Future System Development, aims at sketching the methodological evolution that helps guaranteeing that future systems meet their increasingly critical requirements. Chapter 3 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.