Areas of Mathematics

The present paper concerns the Wittgenstein ontology project: an attempt to create a Semantic Web representation of Ludwig Wittgenstein’s philosophy. The project has been in development since 2006, and its current state enables users to search for information about Wittgenstein-related documents and the documents themselves. However, the developers have much more ambitious goals: they attempt to provide a philosophical subject matter knowledge base that would comprise the claims and concepts formulated by the philosopher. The current knowledge representation technology is not (...) well-suited for this task, and a non-standard approach is required. The creators of the Wittgenstein ontology project are aware of this fact; recently, they have been discussing conceptual devices adjusting the technology to their needs. The main goal of this paper is to present examples of a representation of philosophical content that make use of both the devices already proposed and some new inventions. The represented content comes from the Tractatus Logico-Philosophicus; more specifically, its theses concerning the problems in philosophy of mathematics. (shrink)

Wir betrachten hier jenen Teil der Grundlagenforschung, der die "intui­ tive" oder "inhaltliche" Mathematik, d. h. das, was ein gew6hnlicher Mathematiker unter Mathematik versteht, systematisch beschreibt und analysiert. Im deskriptiven Teil wird die informale Mathematik in einer formal en Sprache (z. B. der der Mengenlehre) neu formuliert. Eine solche Sprache hat, verglichen mit der Sprache der informalen Mathematik, ein sehr eingeschr~nktes Vokabular und eine vollkommen exakte Grammatik; dadurch wird naturlich die Pr~zision erh6ht und der Blick von Unwesentlichem befreit. Im Gegensatz (...) zu einer weitverbreiteten Ansicht, die weiter unten diskutiert wird, ist die Neuformulierung (die wie jede Beschreibung eines intuitiv erfa~ten Gegenstandes wesentlich von unserer Auffassung seiner Natur abh~ngt) nur ein Hilfsmittel der Grundlagenforschung: es handelt sich n~mlich darum, die Bedeutung von S~tzen der informalen Mathematik richtig wiederzugeben und nicht deren syntaktische Struktur; denn der ~u~eren Form nach haben die formale und die informale Sprache (glucklicherweisel) wenig gemeinsam. Auch sollte man bemerken, da~ die durch die Umformulierung erzielte Pr~zision zwar die technische Entwick­ lung f6rdert, aber kaum geeignet ist, Schwierigkeiten zu beseitigen, die aus Unzul~nglichkeiten der ursprunglichen Begriffe entstehen (gerade das Gegenteil ist der Fall: durch Nachdenken uber informale Begriffe werden wir zu einer guten Formalisierung gefuhrt). In den wohlbekannten "Krisen" (siehe z. B. Teil A, Abschnitt 1 weiter unten) ruhrten die Widerspruche von durchaus expliziten Prinzipien (Axiomen, Regeln) her, so da~ diese Schwierigkeiten nichts mit ungenugender formaler Pr~zision zu tun hatten; das Problem lag vielmehr darin, unter verschiedenen, formal pr~zisen Prinzipien die gultigen herauszufinden. (shrink)

López-Escobar, E. G. K. Introduction.--Kueker, D. W. Back-and-forth arguments and infinitary logics.--Green, J. Consistency properties for finite quantifier languages.--Cunningham, E. Chain models.--Gregory, J. On a finiteness condition for infinitary languages.

In diesem Buch werden Aspekte der Aussagenlogik und der Prädikaten­ logik der ersten Stufe behandelt. Eine Mathematisierung und Kalkü­ lisierung der Logik kann natürlich ganz verschieden ausfallen, je nach dem, von welchen Motiven man sich primär leiten läßt. Wir stellen drei Gesichtspunkte, die uns auch als die wesentlichsten erscheinen, in den Vordergrund: Die Formalisierung des Wahrheits­ begriffes, die Formalisierung des Beweisbarkeitsbegriffes und das Problem des Suchens nach Beweisen. Diese drei Aspekte führen zu drei verschiedenen Arten von Kalkülen. Die Betonung des (...) Wahrheitsbegriffes führte auf die untersuchung der Hilberttypkalküle von einem Standpunkt, wie er etwa auch im Buch von Rasiowa-Sikorski [Ra-Si] eingenommen wird. Hierbei wurde besonderen Wert auf die algebraischen Techniken gelegt, denn die Natur der Vollständigkeitsbeweise in diesen Kalkülen läßt sich u. E. eigentlich nur algebraisch verstehen. Etwas überspitzt könnte man formulieren, daß die Vollständigkeitsbeweise in Hilberttypkal­ külen Korollare zu Betrachtungen über Kongruenzrelationen in ge­ wissen Boole'schen Algebren sind. Bei den modelltheoretischen Be­ trachtungen haben wir uns kurz ge faßt und nur einige grundlegende Begriffe vorgestellt. (shrink)

Der Fortschritt der Aussagenlogik in jungster Zeit HiBt es sinnvoll erscheinen, einen breiteren Leserkreis mit dieser Entwicklung bekannt zu machen. Obwohl vorliegendes Buch als Lehrbuch, nicht als Monographie fUr einen engeren Spezialistenkreis konzipiert wurde, soli es in einigen Themen einen tieferen Einblick in den aktuellen Stand der Dinge vermitteln. Kap. lund ein Tei! von Kap. II befassen sich mit der zweiwertigen Aussagenlogik und sind fUr Leser gedacht, die an Logik interessiert sind, doch noch nicht niiher mit ihr befaBt waren. Die (...) etwas breitere Darstellung in diesen Teilen sollte allerdings kein falsches Bild von den wahren Proportionen entstehen lassen. Denn danach nimmt die zweiwertige Aussagenlogik nicht nur innerhalb der Logik insgesamt, sondern schon innerhalb der Aussagenlogik einen Platz ein, der vergleichbar ist mit dem der euklidischen Planimetrie im Rahmen der neueren Geometrie. Lesern mit ausreichenden Vorkennt­ nissen wird es nichts ausmachen, die anfanglichen Teile zu ubergehen und dort zu be­ ginnen, wo Aussagenlogik erst interessant zu werden beginnt, niimlich wo sie den Rahmen zweiwertiger Logik verliiBt. (shrink)

Wenn es eine Aufgabe der Philosophie ist, die Herrschaft des Wortes über den menschlichen Geist zu brechen (Frege), dann ist zu fragen, ob die Prädikatenlogik die Wörter «für alle» und «es gibt» angemessen formalisiert. Übersetzt man «alle Menschen sind sterblich» mit «für alle x : wenn x ein Mensch ist, dann ist x sterblich», so hat man zwar die Syllogistik des Aristoteles überwunden, dafür tritt jetzt aber eine Variable x auf, die in der Aussage vorher nicht vorkam.

Recent debates in metaphysics have highlighted the significance of type theories, such as Simple Type Theory (STT), for our philosophical analysis. In this chapter, I present the salient features of a constructive type theory in the style of Martin-Löf, termed CTT. My principal aim is to convey the flavour of this rich, flexible and sophisticated theory and compare it with STT. I especially focus on the forms of quantification which are available in CTT. A further aim is to argue that (...) a comparison between a plurality of theories is beneficial to the philosophical analysis. We may, for example, discover helpful features of one theory that we may want to import into another context, thus enriching our repertoire of formal tools. Or, through comparison with a less well-known theory, we may gain a better understanding of the characteristics of the theories we are familiar with. As argued in this chapter, CTT has much to offer in all of these respects. (shrink)

This book is dedicated to V.A. Yankov’s seminal contributions to the theory of propositional logics. His papers, published in the 1960s, are highly cited even today. The Yankov characteristic formulas have become a very useful tool in propositional, modal and algebraic logic. The papers contributed to this book provide the new results on different generalizations and applications of characteristic formulas in propositional, modal and algebraic logics. In particular, an exposition of Yankov’s results and their applications in algebraic logic, the theory (...) of admissible rules and refutation systems is included in the book. In addition, the reader can find the studies on splitting and join-splitting in intermediate propositional logics that are based on Yankov-type formulas which are closely related to canonical formulas, and the study of properties of predicate extensions of non-classical propositional logics. The book also contains an exposition of Yankov’s revolutionary approach to constructive proof theory. The editors also include Yankov’s contributions to history and philosophy of mathematics and foundations of mathematics, as well as an examination of his original interpretation of history of Greek philosophy and mathematics. (shrink)

Ce livre est un recueil des articles que l'auteur a publiés dans la rubrique Logique et Calcul du magazine Pour la Science. La sélection a pour thème la logique dans toute sa diversité. Par exemple, elle peut concerner les mathématiques pures : L'infini est-il paradoxal en mathématiques, Libre arbitre et mécanique quantique ou Les limites logiques des mathématiques. Mais on la trouve aussi au coeur d'applications concrètes. Ainsi, L'étonnante loi de Benford, selon laquelle un nombre pris au hasard, par exemple (...) dans le journal, commence plus souvent par un " 1 " plutôt que par tout autre chiffre, permet de dépister les tricheurs. Ou encore, la logique qui aide à répondre à cette question d'actualité : La répartition idéale des biens existe-t-elle? Jean-Paul Delahaye, avec son style et ses talents reconnus de vulgarisateur, nous fait même réfléchir aux liens qui unissent La belle au bois dormant, les extraterrestres et la fin du monde! Idéal en cette année 2012. (shrink)

Type theory is a fast-evolving field at the crossroads of logic, computer science and mathematics. This gentle step-by-step introduction is ideal for graduate students and researchers who need to understand the ins and outs of the mathematical machinery, the role of logical rules therein, the essential contribution of definitions and the decisive nature of well-structured proofs. The authors begin with untyped lambda calculus and proceed to several fundamental type systems culminating in the well-known and powerful Calculus of Constructions. The book (...) also covers the essence of proof checking and proof development, and the use of dependent type theory to formalize mathematics. The only prerequisites are a good knowledge of undergraduate algebra and analysis. Carefully chosen examples illustrate the theory throughout. Each chapter ends with a summary of the content, some historical context, suggestions for further reading and a selection of exercises to help readers familiarize themselves with the material. (shrink)

This book brings together the latest technological research in computational intelligence and fuzzy logic as a way to care for our environment, highlighting current advances and future trends in environmental sustainability using the principles of soft computing.

L'ouvrage invite à penser l'épistémologie non classique des mathématiques comme une construction épistémique des mathématiques quasi empirique qu'Imré Lakatos a réalisé au moyen des présupposés ontologiques (comme la redécouverte du temps, le passage du déterminisme à l'indéterminisme, etc.) et qu'il réussit grâce à l'implémentation du principe de complexité dialectique de l'esprit mathématique. L'auteur étudie la thèse selon laquelle, depuis le début du XXe siècle, la science est aussi bien objective que subjective. Et c'est à partir de celle-ci que le principe (...) de "la complexité dialectique de l'esprit mathématique" est mis au jour pour dévoiler le constructivisme de Lakatos. (shrink)

part 1. Fuzzy logic theory 1 -- part 2. Applications and advanced topics of fuzzy logic.

In the 21st century, digitalization is a global challenge of mankind. Even for the public, it is obvious that our world is increasingly dominated by powerful algorithms and big data. But, how computable is our world? Some people believe that successful problem solving in science, technology, and economies only depends on fast algorithms and data mining. Chances and risks are often not understood, because the foundations of algorithms and information systems are not studied rigorously. Actually, they are deeply rooted in (...) logics, mathematics, computer science and philosophy. Therefore, this book studies the foundations of mathematics, computer science, and philosophy, in order to guarantee security and reliability of the knowledge by constructive proofs, proof mining and program extraction. We start with the basics of computability theory, proof theory, and information theory. In a second step, we introduce new concepts of information and computing systems, in order to overcome the gap between the digital world of logical programming and the analog world of real computing in mathematics and science. The book also considers consequences for digital and analog physics, computational neuroscience, financial mathematics, and the Internet of Things (IoT). (shrink)

Originally published in 1967. An introduction to the literature of nonstandard logic, in particular to those nonstandard logics known as many-valued logics. Part I expounds and discusses implicational calculi, modal logics and many-valued logics and their associated calculi. Part II considers the detailed development of various many-valued calculi, and some of the important metathereoms which have been proved for them. Applications of the calculi to problems in the philosophy are also surveyed. This work combines criticism with exposition to form a (...) comprehensive but concise survey of the field. (shrink)

The term "fuzzy logic," as it is understood in this book, stands for all aspects of representing and manipulating knowledge based on the rejection of the most fundamental principle of classical logic---the principle of bivalence. According to this principle, each declarative sentence is required to be either true or false. In fuzzy logic, these classical truth values are not abandoned. However, additional, intermediate truth values between true and false are allowed, which are interpreted as degrees of truth. This opens a (...) new way of thinking---thinking in terms of degrees rather than absolutes. For example, it leads to the definition of a new kind of sets, referred to as fuzzy sets, in which membership is a matter of degree. The book examines the genesis and development of fuzzy logic. It surveys the prehistory of fuzzy logic and inspects circumstances that eventually lead to the emergence of fuzzy logic. The book explores in detail the development of propositional, predicate, and other calculi that admit degrees of truth, which are known as fuzzy logic in the narrow sense. Fuzzy logic in the broad sense, whose primary aim is to utilize degrees of truth for emulating common-sense human reasoning in natural language, is scrutinized as well. The book also examines principles for developing mathematics based on fuzzy logic and provides overviews of areas in which this has been done most effectively. It also presents a detailed survey of established and prospective applications of fuzzy logic in various areas of human affairs, and provides an assessment of the significance of fuzzy logic as a new paradigm. (shrink)

This collection of new essays presents cutting-edge research on the semantic conception of logic, the invariance criteria of logicality, grammaticality, and logical truth. Contributors explore the history of the semantic tradition, starting with Tarski, and its historical applications, while central criticisms of the tradition, and especially the use of invariance criteria to explain logicality, are revisited by the original participants in that debate. Other essays discuss more recent criticism of the approach, and researchers from mathematics and linguistics weigh in on (...) the role of the semantic tradition in their disciplines. This book will be invaluable to philosophers and logicians alike. (shrink)

We often, in effect, take it for granted that some word or phrase is what is called ‘the name of a class, be that class empty or non-empty’. We do so whenever in effect we either wonder about, or mean to be taking a view on, the number of members a certain suppositious class has, on the ultrasimple number scale: ‘None, more than none’.

Over the past forty years, scientists have developed models of human reasoning based on the principle that human languages and classical logic involve fundamentally different concepts and different methods of interpretation. In The Emergence of Meaning Stephen Crain challenges this view, arguing that a common logical nativism underpins human language and logical reasoning. The approach which Crain takes is twofold. Firstly, he uncovers the underlying meanings of logical expressions and logical principles that appear in typologically different languages - English and (...) Mandarin Chinese - and he demonstrates that these meanings and principles directly correspond to the expressions and structures of classical logic. Secondly he reports the findings of new experimental studies which investigate how children acquire the logical concepts of these languages. A step-by-step introduction to logic and a comprehensive review of the literature on child language acquisition make this work accessible to those unfamiliar with either field. (shrink)