Dirk van Dalen

Dirk van Dalen’s biography studies the fascinating life of the famous Dutch mathematician and philosopher Luitzen Egbertus Jan Brouwer. Brouwer belonged to a special class of genius; complex and often controversial and gifted with a deep intuition, he had an unparalleled access to the secrets and intricacies of mathematics. Most mathematicians remember L.E.J. Brouwer from his scientific breakthroughs in the young subject of topology and for the famous Brouwer fixed point theorem. Brouwer’s main interest, however, was in the foundation of mathematics which led him to introduce, and then consolidate, constructive methods under the name ‘intuitionism’. This made him one of the main protagonists in the ‘foundation crisis’ of mathematics. As a confirmed internationalist, he also got entangled in the interbellum struggle for the ending of the boycott of German and Austrian scientists. This time during the twentieth century was turbulent; nationalist resentment and friction between formalism and intuitionism led to the Mathematische Annalen conflict ('The war of the frogs and the mice'). It was here that Brouwer played a pivotal role. The present biography is an updated revision of the earlier two volume biography in one single book. It appeals to mathematicians and anybody interested in the history of mathematics in the first half of the twentieth century.

Dirk van Dalen’s biography studies the fascinating life of the famous Dutch mathematician and philosopher Luitzen Egbertus Jan Brouwer. Brouwer belonged to a special class of genius; complex and often controversial and gifted with a deep intuition, he had an unparalleled access to the secrets and intricacies of mathematics. Most mathematicians remember L.E.J. Brouwer from his scientific breakthroughs in the young subject of topology and for the famous Brouwer fixed point theorem. Brouwer’s main interest, however, was in the foundation of mathematics which led him to introduce, and then consolidate, constructive methods under the name ‘intuitionism’. This made him one of the main protagonists in the ‘foundation crisis’ of mathematics. As a confirmed internationalist, he also got entangled in the interbellum struggle for the ending of the boycott of German and Austrian scientists. This time during the twentieth century was turbulent; nationalist resentment and friction between formalism and intuitionism led to the Mathematische Annalen conflict ('The war of the frogs and the mice'). It was here that Brouwer played a pivotal role. The present biography is an updated revision of the earlier two volume biography in one single book. It appeals to mathematicians and anybody interested in the history of mathematics in the first half of the twentieth century.

Der mathematische Intuitionismus war die Schöpfung des niederländischen Mathematikers L. E. J. Brouwer, der damit am Anfang des zwanzigsten Jahrhunderts eine konstruktive Neubegründung der Mathematik anstieß. Dieses Buch enthält drei Arbeiten Brouwers aus den 1920er-Jahren, die seine Ansichten und Methoden in ausgereifter Form wiedergeben, sowie Kommentare dazu. Teil I besteht aus seinen im Jahre 1927 gehaltenen Berliner Gastvorlesungen, die die Ouvertüre zu einem erweiterten und vertieften Intuitionismus darstellen. Teil II entstammt einer geplanten aber unvollendeten Monographie über die Neubegründung der Theorie der reellen Funktionen. Teil III bringt abschließend Brouwers Wiener Vortrag „Mathematik, Wissenschaft und Sprache“, in dem er auf Fragen zur philosophischen Grundlage des Intuitionismus einging. Zusammengenommen geben diese drei Texte ein Gesamtbild von Brouwers intuitionistischen Auffassungen zum Höhepunkt des Grundlagenstreits in der Mathematik.

Dirk van Dalen’s popular textbook Logic and Structure, now in its fifth edition, provides a comprehensive introduction to the basics of classical and intuitionistic logic, model theory and Gödel’s famous incompleteness theorem. Propositional and predicate logic are presented in an easy-to-read style using Gentzen’s natural deduction. The book proceeds with some basic concepts and facts of model theory: a discussion on compactness, Skolem-Löwenheim, non-standard models and quantifier elimination. The discussion of classical logic is concluded with a concise exposition of second-order logic. In view of the growing recognition of constructive methods and principles, intuitionistic logic and Kripke semantics is carefully explored. A number of specific constructive features, such as apartness and equality, the Gödel translation, the disjunction and existence property are also included. The last chapter on Gödel's first incompleteness theorem is self-containedand provides a systematic exposition of the necessary recursion theory. This new edition has been properly revised and contains a new section on ultra-products.

O livro-texto popular de Dirk van Dalen, LOgica e Estrutura, agora em sua quinta ediCAo, oferece uma introduCAo abrangente aos fundamentos da lOgica clAssica e da lOgica intuicionIstica, da teoria dos modelos e do famoso teorema da incompletude de GOdel. A lOgica proposicional e a lOgica de predicados sAo apresentadas num estilo fAcil de ler usando a deduCAo natural de Gentzen. O livro prossegue com alguns conceitos e fatos bAsicos da teoria dos modelos: uma discussAo sobre compaccidade, Skolem-LOwenheim, modelos nAo-padrAo e eliminaCAo de quantificadores. A discussAo da lOgica clAssica E encerrada com uma exposiCAo concisa da lOgica de segunda ordem. Em vista do crescente reconhecimento de mEtodos e princIpios construtivos, a lOgica intuicionIstica e a semAntica de Kripke sAo cuidadosamente exploradas. Uma sErie de caracterIsticas construtivas especIficas, como a separaCAo e a igualdade, a traduCAo de GOdel, as propriedades da disjunCAo e da existEncia tambEm foram incluIdas. O Ultimo capItulo sobre o primeiro teorema da incompletude de GOdel E autocontido e fornece uma exposiCAo sistemAtica da teoria da recursAo necessAria. Esta nova ediCAo foi devidamente revisada e contEm uma nova seCAo sobre ultraprodutos.