Axiomatic Set Theory Proceedings of Symposia in Pure Mathematics
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“The Church-Turing “Thesis” As a Special Corollary of Gödel's
“The Church-Turing “Thesis” as a Special Corollary of Gödel’s Completeness Theorem,” in Computability: Turing, Gödel, Church, and Beyond, B. J. Copeland, C. Posy, and O. Shagrir (eds.), MIT Press (Cambridge), 2013, pp. 77-104. Saul A. Kripke This is the published version of the book chapter indicated above, which can be obtained from the publisher at https://mitpress.mit.edu/books/computability. It is reproduced here by permission of the publisher who holds the copyright. © The MIT Press The Church-Turing “ Thesis ” as a Special Corollary of G ö del ’ s 4 Completeness Theorem 1 Saul A. Kripke Traditionally, many writers, following Kleene (1952) , thought of the Church-Turing thesis as unprovable by its nature but having various strong arguments in its favor, including Turing ’ s analysis of human computation. More recently, the beauty, power, and obvious fundamental importance of this analysis — what Turing (1936) calls “ argument I ” — has led some writers to give an almost exclusive emphasis on this argument as the unique justification for the Church-Turing thesis. In this chapter I advocate an alternative justification, essentially presupposed by Turing himself in what he calls “ argument II. ” The idea is that computation is a special form of math- ematical deduction. Assuming the steps of the deduction can be stated in a first- order language, the Church-Turing thesis follows as a special case of G ö del ’ s completeness theorem (first-order algorithm theorem). I propose this idea as an alternative foundation for the Church-Turing thesis, both for human and machine computation. Clearly the relevant assumptions are justified for computations pres- ently known. -
Creating New Concepts in Mathematics: Freedom and Limitations. the Case of Category Theory
Creating new concepts in mathematics: freedom and limitations. The case of Category Theory Zbigniew Semadeni Institute of Mathematics, University of Warsaw Abstract In the paper we discuss the problem of limitations of freedom in mathematics and search for criteria which would differentiate the new concepts stemming from the historical ones from the new concepts that have opened unexpected ways of thinking and reasoning. We also investigate the emergence of category theory (CT) and its origins. In particular we explore the origins of the term functor and present the strong evidence that Eilenberg and Carnap could have learned the term from Kotarbinski´ and Tarski. Keywords categories, functors, Eilenberg-Mac Lane Program, mathematical cognitive transgressions, phylogeny, platonism. CC-BY-NC-ND 4.0 • 1. Introduction he celebrated dictum of Georg Cantor that “The essence of math- Tematics lies precisely in its freedom” expressed the idea that in mathematics one can freely introduce new notions (which may, how- Philosophical Problems in Science (Zagadnienia FilozoficzneNo w Nauce) 69 (2020), pp. 33–65 34 Zbigniew Semadeni ever, be abandoned if found unfruitful or inconvenient).1 This way Cantor declared his opposition to claims of Leopold Kronecker who objected to the free introduction of new notions (particularly those related to the infinite). Some years earlier Richard Dedekind stated that—by forming, in his theory, a cut for an irrational number—we create a new number. For him this was an example of a constructed notion which was a free creation of the human mind (Dedekind, 1872, § 4). In 1910 Jan Łukasiewicz distinguished constructive notions from empirical reconstructive ones. -
Unfolding of Systems of Inductive Definitions
UNFOLDINGOFSYSTEMSOFINDUCTIVE DEFINITIONS A DISSERTATION SUBMITTED TO THE DEPARTMENT OF MATHEMATICS AND THE COMMITTEE OF GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FORTHEDEGREEOF DOCTOROFPHILOSOPHY Ulrik Torben Buchholtz December 2013 © 2013 by Ulrik Torben Buchholtz. All Rights Reserved This work is licensed under the Creative Commons Attribution 3.0 United States License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/us/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA. This dissertation is online at: http://purl.stanford.edu/kg627pm6592 ii I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Solomon Feferman, Primary Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Grigori Mints, Co-Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Thomas Strahm Approved for the Stanford University Committee on Graduate Studies. Patricia J. Gumport, Vice Provost for Graduate Education An original signed hard copy of the signature page is on file in University Archives. iii iv ABSTRACT This thesis is a contribution to Solomon Feferman’s Unfolding Program which aims to provide a general method of capturing the operations on individuals and predicates (and the principles governing them) that are implicit in a formal axiomatic system based on open-ended schemata. -
Notices of the American Mathematical Society
June 18 and 19)- Page 341 Vl 0 ~ Mathematical Society Calendar of AMS Meetings THIS CALENDAR lists all meetings which have been approved by the Council prior to the date this issue of the Notices was sent to press. The summer and annual meetings are joint meetings of the Mathematical Association of America and the Ameri· can Mathematical Society. The meeting dates which fall rather far in the future are subject to change; this is particularly true of meetings to which no numbers have yet been assigned. Programs of the meetings will appear in the issues indicated below. First and second announcements of the meetings will have appeared in earlier issues. ABSTRACTS OF PAPERS presented at a meeting of the Society are published in the journal Abstracts of papers presented to the American Mathematical Society in the issue corresponding to that of the Notices which contains the program of the meet ing. Abstracts should be submitted on special forms which are available in many departments of mathematics and from the office of the Society in Providence. Abstracts of papers to be presented at the meeting must be received at the headquarters of the Society in Providence, Rhode Island, on or before the deadline given below for the meeting. Note that the deadline for ab· stracts submitted for consideration for presentation at special sessions is usually three weeks earlier than that specified below. For additional information consult the meeting announcement and the list of organizers of special sessions. MEETING ABSTRACT NUMBER DATE PLACE DEADLINE -
Toward a Mathematical Semantics for Computer Languages
(! 1 J TOWARD A MATHEMATICAL SEMANTICS FOR COMPUTER LANGUAGES by Dana Scott and - Christopher Strachey Oxford University Computing Laboratory Programming Research Group-Library 8-11 Keble Road Oxford OX, 3QD Oxford (0865) 54141 Oxford University Computing Laboratory Programming Research Group tI. cr• "';' """, ":.\ ' OXFORD UNIVERSITY COMPUTING LABORATORY PROGRAMMING RESEARCH GROUP ~ 4S BANBURY ROAD \LJ OXFORD ~ .. 4 OCT 1971 ~In (UY'Y L TOWARD A ~ATHEMATICAL SEMANTICS FOR COMPUTER LANGUAGES by Dana Scott Princeton University and Christopher Strachey Oxford University Technical Monograph PRG-6 August 1971 Oxford University Computing Laboratory. Programming Research Group, 45 Banbury Road, Oxford. ~ 1971 Dana Scott and Christopher Strachey Department of Philosophy, Oxford University Computing Laboratory. 1879 lIall, Programming Research Group. Princeton University, 45 Banbury Road. Princeton. New Jersey 08540. Oxford OX2 6PE. This pape r is also to appear in Fl'(.'ceedinBs 0;- the .';y-,;;;o:illT:: on ComputeT's and AutoJ7'ata. lo-licroloo'ave Research Institute Symposia Series Volume 21. Polytechnic Institute of Brooklyn. and appears as a Technical Monograph by special aJ"rangement ...·ith the publishers. RefeJ"~nces in the Ii terature should be:- made to the _"!'OL·,-,',~;r:gs, as the texts are identical and the Symposia Sl?ries is gcaerally available in libraries. ABSTRACT Compilers for high-level languages aTe generally constructed to give the complete translation of the programs into machme language. As machines merely juggle bit patterns, the concepts of the original language may be lost or at least obscured during this passage. The purpose of a mathematical semantics is to give a correct and meaningful correspondence between programs and mathematical entities in a way that is entirely independent of an implementation. -
Why Mathematical Proof?
Why Mathematical Proof? Dana S. Scott, FBA, FNAS University Professor Emeritus Carnegie Mellon University Visiting Scholar University of California, Berkeley NOTICE! The author has plagiarized text and graphics from innumerable publications and sites, and he has failed to record attributions! But, as this lecture is intended as an entertainment and is not intended for publication, he regards such copying, therefore, as “fair use”. Keep this quiet, and do please forgive him. A Timeline for Geometry Some Greek Geometers Thales of Miletus (ca. 624 – 548 BC). Pythagoras of Samos (ca. 580 – 500 BC). Plato (428 – 347 BC). Archytas (428 – 347 BC). Theaetetus (ca. 417 – 369 BC). Eudoxus of Cnidus (ca. 408 – 347 BC). Aristotle (384 – 322 BC). Euclid (ca. 325 – ca. 265 BC). Archimedes of Syracuse (ca. 287 – ca. 212 BC). Apollonius of Perga (ca. 262 – ca. 190 BC). Claudius Ptolemaeus (Ptolemy)(ca. 90 AD – ca. 168 AD). Diophantus of Alexandria (ca. 200 – 298 AD). Pappus of Alexandria (ca. 290 – ca. 350 AD). Proclus Lycaeus (412 – 485 AD). There is no Royal Road to Geometry Euclid of Alexandria ca. 325 — ca. 265 BC Euclid taught at Alexandria in the time of Ptolemy I Soter, who reigned over Egypt from 323 to 285 BC. He authored the most successful textbook ever produced — and put his sources into obscurity! Moreover, he made us struggle with proofs ever since. Why Has Euclidean Geometry Been So Successful? • Our naive feeling for space is Euclidean. • Its methods have been very useful. • Euclid also shows us a mysterious connection between (visual) intuition and proof. The Pythagorean Theorem Euclid's Elements: Proposition 47 of Book 1 The Pythagorean Theorem Generalized If it holds for one Three triple, Similar it holds Figures for all. -
Ralph Martin Kaufmann Publications 1. Kaufmann, Ralph
Ralph Martin Kaufmann Department of Mathematics, Purdue University 150 N. University Street, West Lafayette, IN 47907{2067 Tel.: (765) 494-1205 Fax: (765) 494-0548 Publications 1. Kaufmann, Ralph M., Khlebnikov, Sergei, and Wehefritz-Kaufmann, Birgit \Local models and global constraints for degeneracies and band crossings" J. of Geometry and Physics 158 (2020) 103892. 2. Galvez-Carillo, Imma, Kaufmann, Ralph M., and Tonks, Andrew. \Three Hopf algebras from number theory, physics & topology, and their common background I: operadic & simplicial aspects" Comm. in Numb. Th. and Physics (CNTP), vol 14,1 (2020), 1-90. 3. Galvez-Carillo, Imma, Kaufmann, Ralph M., and Tonks, Andrew. \Three Hopf algebras from number theory, physics & topology, and their common background II: general categorical formulation" Comm. in Numb. Th. and Physics (CNTP), vol 14,1 (2020), 91-169. 4. Kaufmann, Ralph M. \Lectures on Feynman categories", 2016 MATRIX annals, 375{438, MATRIX Book Ser., 1, Springer, Cham, 2018. 5. Kaufmann, Ralph M. and Kaufmann-Wehfritz, B. Theoretical Properties of Materials Formed as Wire Network Graphs from Triply Periodic CMC Surfaces, Especially the Gyroid in: \The Role of Topology in Materials", Eds: Gupta, S. and Saxena, A., Springer series in Solid State Sciences. Springer, 2018 6. Kaufmann, Ralph and Lucas, Jason. \Decorated Feynman categories". J. of Noncommutative Geometry, 1 (2017), no 4 1437-1464 7. Berger, C. and Kaufmann R. M. \Comprehensive Factorization Systems". Special Issue in honor of Professors Peter J. Freyd and F.William Lawvere on the occasion of their 80th birthdays, Tbilisi Mathematical Journal 10 (2017), no. 3,. 255-277 8. Kaufmann, Ralph M. -
The Origins of Structural Operational Semantics
The Origins of Structural Operational Semantics Gordon D. Plotkin Laboratory for Foundations of Computer Science, School of Informatics, University of Edinburgh, King’s Buildings, Edinburgh EH9 3JZ, Scotland I am delighted to see my Aarhus notes [59] on SOS, Structural Operational Semantics, published as part of this special issue. The notes already contain some historical remarks, but the reader may be interested to know more of the personal intellectual context in which they arose. I must straightaway admit that at this distance in time I do not claim total accuracy or completeness: what I write should rather be considered as a reconstruction, based on (possibly faulty) memory, papers, old notes and consultations with colleagues. As a postgraduate I learnt the untyped λ-calculus from Rod Burstall. I was further deeply impressed by the work of Peter Landin on the semantics of pro- gramming languages [34–37] which includes his abstract SECD machine. One should also single out John McCarthy’s contributions [45–48], which include his 1962 introduction of abstract syntax, an essential tool, then and since, for all approaches to the semantics of programming languages. The IBM Vienna school [42, 41] were interested in specifying real programming languages, and, in particular, worked on an abstract interpreting machine for PL/I using VDL, their Vienna Definition Language; they were influenced by the ideas of McCarthy, Landin and Elgot [18]. I remember attending a seminar at Edinburgh where the intricacies of their PL/I abstract machine were explained. The states of these machines are tuples of various kinds of complex trees and there is also a stack of environments; the transition rules involve much tree traversal to access syntactical control points, handle jumps, and to manage concurrency. -
An Interview with F. William Lawvere
An Interview with F. William Lawvere You have written a paper, published for the first time in 1986, entitled \Taking categories seriously"1. Why should we take categories seriously ? In all those areas where category theory is actively used the categorical concept of adjoint functor has come to play a key role. Such a universal instrument for guiding the learning, development, and use of advanced mathematics does not fail to have its indications also in areas of school and college mathematics, in the most basic relationships of space and quantity and the calculations based on those relationships. By saying \take categories seriously", I meant that one should seek, cultivate, and teach helpful examples of an elementary nature. The relation between teaching and research is partly embodied in simple general concepts that can guide the elaboration of examples in both. No- tions and constructions, such as the spectral analysis of dynamical systems, have important aspects that can be understood and pursued without the complications of limiting the models to specific classical categories. The application of some simple general concepts from category theory can lead from a clarification of basic con- structions on dynamical systems to a F. William Lawvere (Braga, March 2007) construction of the real number system with its structure as a closed cate- gory; applied to that particular closed category, the general enriched category theory leads inexorably to embedding the- orems and to notions of Cauchy completeness, rotation, convex hull, radius, and 1Revista Colombiana de Matematicas 20 (1986) 147-178. Reprinted in Repr. Theory Appl. Categ. 8 (2005) 1-24 (electronic). -
Proof Theory Synthese Library
PROOF THEORY SYNTHESE LIBRARY STUDIES IN EPISTEMOLOGY, LOGIC, METHODOLOGY, AND PHILOSOPHY OF SCIENCE Managing Editor: JAAKKO HINTIKKA, Boston University Editors: DIRK VAN DALEN, University of Utrecht, The Netherlands DONALD DAVIDSON, University of California, Berkeley THEO A.F. KUIPERS, University of Groningen, The Netherlands PATRICK SUPPES, Stanford University, California JAN WOLENSKI, iagiellonian University, Krakow, Poland VOLUME 292 PROOF THEORY History and Philosophical Significance Edited by VINCENT F. HENDRICKS University of Copenhagen. Denmark STIG ANDUR PEDERSEN and KLAUS FROVIN J0RGENSEN University of Roskilde, Denmark SPRINGER-SCIENCE+BUSINESS MEDIA, B.V. A c.I.P. Catalogue record for this book is available from the Library of Congress. ISBN 978-90-481-5553-8 ISBN 978-94-017-2796-9 (eBook) DOI 10.1007/978-94-017-2796-9 Printed on acid-free paper All Rights Reserved © 2000 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 2000 Softcover reprint of the hardcover 1st edition 2000 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner. CONTENTS Preface ................................................................. ix Contributing Authors ................................................. , xi HENDRICKS, PEDERSEN AND J0RGENSEN / Introduction .......... 1 PART 1. REVIEW OF PROOF THEORY SOLOMON FEFERMAN / Highlights in Proof Theory ................ , 11 1. Review of Hilbert's Program and Finitary Proof Theory ......... , 11 2. Results of Finitary Proof Theory via Gentzen's L-Calculi ......... 14 3. Shifting Paradigms .............................................. 21 4. Countably Infinitary Methods (Getting the Most Out of Logic) .. -
GRASSMANN's DIALECTICS and CATEGORY THEORY in Several
F. WILLIAM LAWVERE GRASSMANN'S DIALECTICS AND CATEGORY THEORY PROGRAMMATIC OUTLINE In several key connections in his foundations of geometrical algebra, Grassmann makes significant use of the dialectical philosophy of 150 years ago. Now, after fifty years of development of category theory as a means for making explicit some nontrivial general arguments in geometry, it is possible to recover some of Grassmann's insights and to express these in ways comprehensible to the modem geometer. For example, the category J/. of affine-linear spaces and maps (a monument to Grassmann) has a canonical adjoint functor to the category of (anti)commutative graded algebras, which as in Grassmann's detailed description yields a sixteen-dimensional algebra when applied to a three dimensional affine space (unlike the eight-dimensional exterior algebra of a three-dimensional vector space). The natural algebraic structure of these algebras includes a boundary operator d which satisfies the (signed) Leibniz rule; for example, if A, B are points of the affine space then the product AB is the axial vector from A to B which the boundary degrades to the corresponding translation vector: d(AB) = B-A (since dA = dB = I for points). Grassmann philosophically motivated a notion of a "simple law of change," but his editors in the 1890' s found this notion incoherent and decided he must have meant mere translations. However, translations are insufficient for the foundational task of deciding when two formal products are geometrically equal axial vectors. But if "Iaw of change" is understood as an action of the additive monoid of time, "simple" turns out to mean that the action is internal to the category J/. -
Actor Model of Computation
Published in ArXiv http://arxiv.org/abs/1008.1459 Actor Model of Computation Carl Hewitt http://carlhewitt.info This paper is dedicated to Alonzo Church and Dana Scott. The Actor model is a mathematical theory that treats “Actors” as the universal primitives of concurrent digital computation. The model has been used both as a framework for a theoretical understanding of concurrency, and as the theoretical basis for several practical implementations of concurrent systems. Unlike previous models of computation, the Actor model was inspired by physical laws. It was also influenced by the programming languages Lisp, Simula 67 and Smalltalk-72, as well as ideas for Petri Nets, capability-based systems and packet switching. The advent of massive concurrency through client- cloud computing and many-core computer architectures has galvanized interest in the Actor model. An Actor is a computational entity that, in response to a message it receives, can concurrently: send a finite number of messages to other Actors; create a finite number of new Actors; designate the behavior to be used for the next message it receives. There is no assumed order to the above actions and they could be carried out concurrently. In addition two messages sent concurrently can arrive in either order. Decoupling the sender from communications sent was a fundamental advance of the Actor model enabling asynchronous communication and control structures as patterns of passing messages. November 7, 2010 Page 1 of 25 Contents Introduction ............................................................ 3 Fundamental concepts ............................................ 3 Illustrations ............................................................ 3 Modularity thru Direct communication and asynchrony ............................................................. 3 Indeterminacy and Quasi-commutativity ............... 4 Locality and Security ............................................