This book outlines the scientific career of Arto Salomaa, a pioneer in theoretical computer science and mathematics. The author first interviewed the subject and his family and collaborators, and he then researched this fascinating biography of an intellectual who was key in the development of these fields. Early chapters progress chronologically from Academician Salomaa's origins, childhood, and education to his professional successes in science, teaching, and publishing. His most impactful direct research efforts have been in the areas of automata and formal languages. Beyond that he has influenced many more scientists and professionals through collaborations, teaching, and books on topics such as biocomputing and cryptography. The author offers insights into Finnish history, culture, and academia, while historians of computer science will appreciate the vignettes describing some of the people who have shaped the field from the 1950s to today. The author and his subject return throughout to underlying themes such as the importance of family and the value of longstanding collegial relationships, while the work and achievements are leavened with humor and references to interests such as music, sport, and the sauna.

This book is dedicated to Aristid Lindenmayer on the occasion of his 60th birthday on November 17, 1985. Contributions range from mathematics and theoretical computer science to biology. Aristid Lindenmayer introduced language-theoretic models for developmental biology in 1968. Since then the models have been cus tomarily referred to as L systems. Lindenmayer's invention turned out to be one of the most beautiful examples of interdisciplinary science: work in one area (developmental biology) induces most fruitful ideas in other areas (theory of formal languages and automata, and formal power series). As evident from the articles and references in this book, the in terest in L systems is continuously growing. For newcomers the first contact with L systems usually happens via the most basic class of L systems, namely, DOL systems. Here "0" stands for zero context between developing cells. It has been a major typographical problem that printers are unable to distinguish between 0 (zero) and 0 (oh). Thus, DOL was almost always printed with "oh" rather than "zero", and also pronounced that way. However, this misunderstanding turned out to be very fortunate. The wrong spelling "DOL" of "DOL" could be read in the suggestive way: DO L Indeed, hundreds of researchers have followed this suggestion. Some of them appear as contributors to this book. Of the many who could not contribute, we in particular regret the absence of A. Ehrenfeucht, G. Herman and H.A. Maurer whose influence in the theory of L systems has been most significant.

The finite - infinite interplay is central in human thinking, from ancient philosophers and mathematicians (Zeno, Pythagoras), to modern mathe matics (Cantor, Hilbert) and computer science (Turing, Godel). Recent developments in mathematics and computer science suggest a) radically new answers to classical questions (e. g. , does infinity exist?, where does infinity come from?, how to reconcile the finiteness of the human brain with the infinity of ideas it produces?), b) new questions of debate (e. g. , what is the role played by randomness?, are computers capable of handling the infinity through unconventional media of computation?, how can one approximate efficiently the finite by the infinite and, conversely, the infinite by finite?). Distinguished authors from around the world, many of them architects of the mathematics and computer science for the new century, contribute to the volume. Papers are as varied as Professor Marcus' activity, to whom this volume is dedicated. They range from real analysis to DNA com puting, from linguistics to logic, from combinatorics on words to symbolic dynamics, from automata theory to geography, and so on, plus an incursion into the old history of conceptions about infinity and a list of philosophical "open problems". They are mainly mathematical and theoretical computer science texts, but not all of them are purely mathematical.

Systematically teaches key paradigmic algorithm design methods Provides a deep insight into randomization