Content Description #Includes bibliographical references and index.

This volume constitutes the proceedings of the Fourth International Symposium on Theoretical Aspects of Computer Software (TACS 2001) held at Tohoku U- versity, Sendai, Japan in October 2001. The TACS symposium focuses on the theoretical foundations of progr- ming and their applications. As this volume shows, TACS is an international symposium, with participants from many di?erent institutions and countries. TACS 2001 was the fourth symposium in the TACS series, following TACS’91, TACS’94, and TACS’97, whose proceedings were published as Volumes 526, 789, and 1281, respectively, of Springer-Verlag’s Lecture Notes in Computer Science series. The TACS 2001 technical program consisted of invited talks and contributed talks. In conjunction with this program there was a special open lecture by Benjamin Pierce; this lecture was open to non-registrants. TACS 2001 bene?ted from the e?orts of many people; in particular, members of the Program Committee and the Organizing Committee. Our special thanks go to the Program Committee Co-chairs: Naoki Kobayashi (Tokyo Institute of Technology) Benjamin Pierce (University of Pennsylvania).

This volume contains the proceedings of the Second International Symposium on Theoretical Aspects of Computer Science, held at Tohoku University, Japan in April 1994. This top-level international symposium on theoretical computer science is devoted to theoretical aspects of programming, programming languages and system, and parallel and distributed computation. The papers in the volume are grouped into sessions on: lambda calculus and programming; automated deduction; functional programming; objects and assignments; concurrency; term rewriting and process equivalence; type theory and programming; algebra, categories and linear logic; and subtyping, intersection and union types. The volume also includes seven invited talks and two open lectures.

TACS'91 is the first International Conference on Theoretical Aspects of Computer Science held at Tohoku University, Japan, in September 1991. This volume contains 37 papers and an abstract for the talks presented at the conference. TACS'91 focused on theoretical foundations of programming, and theoretical aspects of the design, analysis and implementation of programming languages and systems. The following range of topics is covered: logic, proof, specification and semantics of programs and languages; theories and models of concurrent, parallel and distributed computation; constructive logic, category theory, and type theory in computer science; theory-based systems for specifying, synthesizing, transforming, testing, and verifying software.

The past 50 years have witnessed a revolution in computing and related communications technologies. The contributions of industry and university researchers to this revolution are manifest; less widely recognized is the major role the federal government played in launching the computing revolution and sustaining its momentum. Funding a Revolution examines the history of computing since World War II to elucidate the federal government's role in funding computing research, supporting the education of computer scientists and engineers, and equipping university research labs. It reviews the economic rationale for government support of research, characterizes federal support for computing research, and summarizes key historical advances in which government-sponsored research played an important role. Funding a Revolution contains a series of case studies in relational databases, the Internet, theoretical computer science, artificial intelligence, and virtual reality that demonstrate the complex interactions among government, universities, and industry that have driven the field. It offers a series of lessons that identify factors contributing to the success of the nation's computing enterprise and the government's role within it.

An accessible and rigorous textbook for introducing undergraduates to computer science theory What Can Be Computed? is a uniquely accessible yet rigorous introduction to the most profound ideas at the heart of computer science. Crafted specifically for undergraduates who are studying the subject for the first time, and requiring minimal prerequisites, the book focuses on the essential fundamentals of computer science theory and features a practical approach that uses real computer programs (Python and Java) and encourages active experimentation. It is also ideal for self-study and reference. The book covers the standard topics in the theory of computation, including Turing machines and finite automata, universal computation, nondeterminism, Turing and Karp reductions, undecidability, time-complexity classes such as P and NP, and NP-completeness, including the Cook-Levin Theorem. But the book also provides a broader view of computer science and its historical development, with discussions of Turing's original 1936 computing machines, the connections between undecidability and Gödel's incompleteness theorem, and Karp's famous set of twenty-one NP-complete problems. Throughout, the book recasts traditional computer science concepts by considering how computer programs are used to solve real problems. Standard theorems are stated and proven with full mathematical rigor, but motivation and understanding are enhanced by considering concrete implementations. The book's examples and other content allow readers to view demonstrations of—and to experiment with—a wide selection of the topics it covers. The result is an ideal text for an introduction to the theory of computation. An accessible and rigorous introduction to the essential fundamentals of computer science theory, written specifically for undergraduates taking introduction to the theory of computation Features a practical, interactive approach using real computer programs (Python in the text, with forthcoming Java alternatives online) to enhance motivation and understanding Gives equal emphasis to computability and complexity Includes special topics that demonstrate the profound nature of key ideas in the theory of computation Lecture slides and Python programs are available at whatcanbecomputed.com

There are several theories of programming. The first usable theory, often called "Hoare's Logic", is still probably the most widely known. In it, a specification is a pair of predicates: a precondition and postcondition (these and all technical terms will be defined in due course). Another popular and closely related theory by Dijkstra uses the weakest precondition predicate transformer, which is a function from programs and postconditions to preconditions. lones's Vienna Development Method has been used to advantage in some industries; in it, a specification is a pair of predicates (as in Hoare's Logic), but the second predicate is a relation. Temporal Logic is yet another formalism that introduces some special operators and quantifiers to describe some aspects of computation. The theory in this book is simpler than any of those just mentioned. In it, a specification is just a boolean expression. Refinement is just ordinary implication. This theory is also more general than those just mentioned, applying to both terminating and nonterminating computation, to both sequential and parallel computation, to both stand-alone and interactive computation. And it includes time bounds, both for algorithm classification and for tightly constrained real-time applications.

This Third Edition, in response to the enthusiastic reception given by academia and students to the previous edition, offers a cohesive presentation of all aspects of theoretical computer science, namely automata, formal languages, computability, and complexity. Besides, it includes coverage of mathematical preliminaries. NEW TO THIS EDITION • Expanded sections on pigeonhole principle and the principle of induction (both in Chapter 2) • A rigorous proof of Kleene’s theorem (Chapter 5) • Major changes in the chapter on Turing machines (TMs) – A new section on high-level description of TMs – Techniques for the construction of TMs – Multitape TM and nondeterministic TM • A new chapter (Chapter 10) on decidability and recursively enumerable languages • A new chapter (Chapter 12) on complexity theory and NP-complete problems • A section on quantum computation in Chapter 12. • KEY FEATURES • Objective-type questions in each chapter—with answers provided at the end of the book. • Eighty-three additional solved examples—added as Supplementary Examples in each chapter. • Detailed solutions at the end of the book to chapter-end exercises. The book is designed to meet the needs of the undergraduate and postgraduate students of computer science and engineering as well as those of the students offering courses in computer applications.