In computing science design plays an eminently important role. By now, it is quite clear that the issue of proper design of programs within a formal calculus is one of the most interesting and most difficult parts of computing science. Many demanding problems have to be envisaged here such as notations, rules and calculi, and the study of semantic models. We are 'far away from comprehensive and widely accepted solutions in these areas. Discussions at the summer school have clearly shown that people have quite different perspectives and priorities with respect to these three main areas. There is a general agreement that notation is very important. Here, notation is not so much used in the sense of "syntactic sugar", but rather in the sense of abstract syntax, in the sense of language constructs. Proper notation can significantly improve our understanding of the nature of the objects that we are dealing with and simplify the formal manipulation of these objects. However, influenced by educational background, habits, and schools of thought there are quite different tastes with respect to notation. The papers in these proceedings show very clearly how different those notations can be even when talking about quite similar objects.

The Marktoberdorf Summer Schools on Informatics were started in 1970, with the intention to convene every second or third year a group of top researchers in computing, devoted to preach their most recent results to an elite of advanced students - young and most promising people - and prepared to stand their questions, criticism and suggestions. The themes of these Advanced Study In stitutes under the sponsorship of the NATO Scientific Affairs Division varied slightly over the years, oscillating more or less around Programming Methodo logy, as the following list shows: 1970 Data Structures and Computer Systems 1971 Program Structures and Fundamental Concepts of Programming 1973 Structured Programming and Programmed Structures 1975 Language Hierarchies and Interfaces 1978 Program Construction 1981 Theoretical Foundations of Programming Methodology 1984 Control Flow and Data Flow: Concepts of Distributed Programming 1986 Logic of Programming and Calculi of Discrete Design 1988 Constructive Methods in Computing Science 1989 Logic, Algebra, and Computation Logic, Algebra, and Computation is the theme of the summer school to which this volume is devoted. It is the tenth in succession, but it is also the first in a new series (the "blue" series) that is intended to alternate in future with the traditional (the "red" series) arrangement; in fact the tenth summer school in the "red" series with the title "Programming and Mathematical Method" , held in 1990, was the subject of celebrating both its serial number and the twenty years of Marktoberdorf Summer Schools altogether.

Mathematics plays a key role in computer science, some researchers would consider computers as nothing but the physical embodiment of mathematical systems. And whether you are designing a digital circuit, a computer program or a new programming language, you need mathematics to be able to reason about the design -- its correctness, robustness and dependability. This book covers the foundational mathematics necessary for courses in computer science. The common approach to presenting mathematical concepts and operators is to define them in terms of properties they satisfy, and then based on these definitions develop ways of computing the result of applying the operators and prove them correct. This book is mainly written for computer science students, so here the author takes a different approach: he starts by defining ways of calculating the results of applying the operators and then proves that they satisfy various properties. After justifying his underlying approach the author offers detailed chapters covering propositional logic, predicate calculus, sets, relations, discrete structures, structured types, numbers, and reasoning about programs. The book contains chapter and section summaries, detailed proofs and many end-of-section exercises -- key to the learning process. The book is suitable for undergraduate and graduate students, and although the treatment focuses on areas with frequent applications in computer science, the book is also suitable for students of mathematics and engineering.

This volume contains the proceedings of ICTAC 2005, the second ICTAC, International Colloquium on Theoretical Aspects of Computing. ICTAC 2005 took place in Hanoi, Vietnam, October 17–21, 2005. ICTAC was founded by the International Institute for Software Technology of the United Nations University (UNU-IIST) to serve as a forum for practiti- ers, lecturers and researchers from academia, industry and government who are interested in theoretical aspects of computing and rigorous approaches to so- ware engineering. The colloquium is aimed particularly, but not exclusively, at participants from developing countries. We believe that this will help developing countries to strengthen their research, teaching and development in computer science and engineering, improve the links between developing countries and developed countries, and establish collaboration in research and education. By providingavenueforthediscussionofcommonproblemsandtheirsolutions,and for the exchangeof experiencesand ideas,this colloquiumsupportsresearchand development in computer science and software technology. ICTAC is attracting more and more attention from more and more countries.

This book constitutes the refereed proceedings of the 9th Asian Symposium on Programming Languages and Systems, APLAS 2011, held in Kenting, Taiwan, in December 2011. The 22 revised full papers presented together with 4 invited talks and one system and tool presentations were carefully reviewed and selected from 64 submissions. The papers are organized in topical sections on program analysis; functional programming; compiler; concurrency; semantics; as well as certification and logic.

The second half of this century will remain as the era of proliferation of electronic computers. They did exist before, but they were mechanical. During next century they may perform other mutations to become optical or molecular or even biological. Actually, all these aspects are only fancy dresses put on mathematical machines. This was always recognized to be true in the domain of software, where "machine" or "high level" languages are more or less rigourous, but immaterial, variations of the universaly accepted mathematical language aimed at specifying elementary operations, functions, algorithms and processes. But even a mathematical machine needs a physical support, and this is what hardware is all about. The invention of hardware description languages (HDL's) in the early 60's, was an attempt to stay longer at an abstract level in the design process and to push the stage of physical implementation up to the moment when no more technology independant decisions can be taken. It was also an answer to the continuous, exponential growth of complexity of systems to be designed. This problem is common to hardware and software and may explain why the syntax of hardware description languages has followed, with a reasonable delay of ten years, the evolution of the programming languages: at the end of the 60's they were" Algol like" , a decade later "Pascal like" and now they are "C or ADA-like". They have also integrated the new concepts of advanced software specification languages.