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2008 | Buch

New Computational Paradigms

Changing Conceptions of What is Computable

herausgegeben von: S. Barry Cooper, Benedikt Löwe, Andrea Sorbi

Verlag: Springer New York

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Über dieses Buch

In recent years, classical computability has expanded beyond its original scope to address issues related to computability and complexity in algebra, analysis, and physics. The deep interconnection between "computation" and "proof" has originated much of the most significant work in constructive mathematics and mathematical logic of the last 70 years. Moreover, the increasingly compelling necessity to deal with computability in the real world (such as computing on continuous data, biological computing, and physical models) has brought focus to new paradigms of computation that are based on biological and physical models. These models address questions of efficiency in a radically new way and even threaten to move the so-called Turing barrier, i.e. the line between the decidable and the un-decidable.

This book examines new developments in the theory and practice of computation from a mathematical perspective, with topics ranging from classical computability to complexity, from biocomputing to quantum computing. The book opens with an introduction by Andrew Hodges, the Turing biographer, who analyzes the pioneering work that anticipated recent developments concerning computation’s allegedly new paradigms. The remaining material covers traditional topics in computability theory such as relative computability, theory of numberings, and domain theory, in addition to topics on the relationships between proof theory, computability, and complexity theory. New paradigms of computation arising from biology and quantum physics are also discussed, as well as the computability of the real numbers and its related issues.

This book is suitable for researchers and graduate students in mathematics, philosophy, and computer science with a special interest in logic and foundational issues. Most useful to graduate students are the survey papers on computable analysis and biological computing. Logicians and theoretical physicists will also benefit from this book.

Inhaltsverzeichnis

Frontmatter

The Turing Model of Computation and its Applications to Logic, Mathematics, Philosophy, and Computer Science

Alan Turing, Logical and Physical
Alan M. Turing (1912–1954), the founder of computability theory, is generally considered a pure logician. But his ideas involved the practical and physical implementation of logical structure, particularly concerned with the relationship between discrete and continuous, and his scientific work both began and ended in theoretical physics.
Andrew Hodges
Computability and Numberings
Serikzhan Badaev, Sergey Goncharov
Computation as Conversation
Johan van Benthem
Computation Paradigms in Light of Hilbert's Tenth Problem
This is a survey of a century-long history of interplay between Hilbert’s tenth problem (about solvability of Diophantine equations) and different notions and ideas from Computability Theory. The present paper is an extended version of [83].
Yuri Matiyasevich
Elementary Algorithms and Their Implementations
In the sequence of articles [3, 4, 5, 6, 7], Moschovakis has proposed a mathematical modeling of the notion of algorithm—a set-theoretic “definition” of algorithms, much like the “definition” of real numbers as Dedekind cuts on the rationals or that of random variables as measurable functions on a probability space. The aim is to provide a traditional foundation for the theory of algorithms, a development of it within axiomatic set theory in the same way as analysis and probability theory are rigorously developed within set theory on the basis of the set theoretic modeling of their basic notions. A characteristic feature of this approach is the adoption of a very abstract notion of algorithm that takes recursion as a primitive operation and is so wide as to admit “non-implementable” algorithms: implementations are special, restricted algorithms (which include the familiar models of computation, e.g., Turing and random access machines), and an algorithm is implementable if it is reducible to an implementation.
Yiannis N. Moschovakis, Vasilis Paschalis
Applications of the Kleene–Kreisel Density Theorem to Theoretical Computer Science
The Kleene–Kreisel density theorem is one of the tools used to investigate the denotational semantics of programs involving higher types.We give a brief introduction to the classic density theorem, then show how this may be generalized to set theoretical models for algorithms accepting real numbers as inputs, and finally survey some recent applications of this generalization.
Dag Normann
Church Without Dogma: Axioms for Computability
Church’s and Turing’s theses assert dogmatically that an informal notion of effective calculability is captured adequately by a particular mathematical concept of computabilty. I present analyses of calculability that are embedded in a rich historical and philosophical context, lead to precise concepts, and dispense with theses.
To investigate effective calculability is to analyze processes that can in principle be carried out by calculators. This is a philosophical lesson we owe to Turing. Drawing on that lesson and recasting work of Gandy, I formulate boundedness and locality conditions for two types of calculators, namely, human computing agents and mechanical computing devices (or discrete machines). The distinctive feature of the latter is that they can carry out parallel computations.
Representing human and machine computations by discrete dynamical systems, the boundedness and locality conditions can be captured through axioms for Turing computors and Gandy machines; models of these axioms are all reducible to Turing machines. Cellular automata and a variety of artificial neural nets can be shown to satisfy the axioms for machine computations.
Wilfried Sieg
Computability on Topological Spaces via Domain Representations
Domains are ordered structures designed to model computation with approximations. We give an introduction to the theory of computability for topological spaces based on representing topological spaces and algebras using domains. Among the topics covered are different approaches to computability on topological spaces; orderings, approximations, and domains; making domain representations; effective domains; classifying representations; type two effectivity and domains; and special representations for inverse limits, regular spaces, and metric spaces. Lastly, we sketch a variety of applications of the theory in algebra, calculus, graphics, and hardware.
Viggo Stoltenberg-Hansen, John V. Tucker
On the Power of Broadcasting in Mobile Computing
A computational model reflecting fundamental computational aspects of wirelessly communicating mobile processors is presented. In essence, our model is a deterministic Turing machine that can launch new processes among which a wireless communication via explicitly assigned channels must be programmed. We show that computations of such machines are polynomially time- and space-equivalent to the synchronized alternating Turing machines studied previously in the literature. This shows that nondeterminism can be completely eliminated from synchronized alternation at the price of introducing a program-driven communication among the respective processors.
Jiří Wiedermann, Dana Pardubská

Logic, Algorithms and Complexity

The Computational Power of Bounded Arithmetic from the Predicative Viewpoint
This paper considers theories of bounded arithmetic that are predicative in the sense of Nelson, that is, theories that are interpretable in Robinson’s Q.We give a nearly exact characterization of functions that can be total in predicative bounded theories. As an upper bound, any such function has a polynomial growth rate and its bit-graph is in nondeterministic exponential time and in co-nondeterministic exponential time. In fact, any function uniquely defined in a bounded theory of arithmetic lies in this class. Conversely, any function that is in this class (provably in IΔ0+exp) can be uniquely defined and total in a (predicative) bounded theory of arithmetic.
Samuel R. Buss
Effective Uniform Bounds from Proofs in Abstract Functional Analysis
Ulrich Kohlenbach
Effective Fractal Dimension in Algorithmic Information Theory
Effective fractal dimension was defined by Lutz (2003) in order to quantitatively analyze the structure of complexity classes, but then interesting connections of effective dimension with information theory were also found, justifying the long existent intuition that dimension is an information content measure. Considering different bounds on computing power that range from finite memory to constructibility, including time-bounded and space-bounded computations, we review all known characterizations of effective dimension that support the thesis that effective dimensions capture what can be considered the inherent information content of a sequence in each setting.
Elvira Mayordomo
Metamathematical Properties of Intuitionistic Set Theories with Choice Principles
This paper is concerned with metamathematical properties of intuitionistic set theories with choice principles. It is proved that the disjunction property, the numerical existence property, Church’s rule, and several other metamathematical properties hold true for constructive Zermelo–Fraenkel Set Theory and full intuitionistic Zermelo–Fraenkel augmented by any combination of the principles of countable choice, dependent choices, and the presentation axiom. Also Markov’s principle may be added.
Michael Rathjen
New Developments in Proofs and Computations
Helmut Schwichtenberg

Models of Computation from Nature

From Cells to (Silicon) Computers, and Back
Although the whole history of computer science is marked by events related to and inspired from “computations” taking place in living cells and organisms (human being included), in the last decades, this became a mainstream research direction, with important and well-established areas, such as evolutionary computing and neural computing, and with exciting new areas, such as DNA and membrane (cellular) computing. All these have both consequences on the efficiency of using standard computers, hopefully leading also to new types of hardware, and—maybe more importantly—on the very understanding of the notion of computing and, at the edge of science towards science fiction. Topics of this kind will be touched in the paper, mainly in relation with DNA and membrane computing.
Gheorghe Păun
Computer Science, Informatics, and Natural Computing—Personal Reflections
The paper presents personal reflections on natural computing: its scope, some of its history, and its relationship to (and the influence on) computer science. It also reflects on the nature of computer science, and argues why “informatics” is a better term than “computer science”.
Grzegorz Rozenberg

Computable Analysis and Real Computation

A Survey on Continuous Time Computations
We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature.
Olivier Bournez, Manuel L. Campagnolo
A Tutorial on Computable Analysis
Vasco Brattka, Peter Hertling, Klaus Weihrauch
A Continuous Derivative for Real-Valued Functions
Abbas Edalat
Infinite Time Computable Model Theory
Joel David Hamkins, Russell Miller, Daniel Seabold, Steve Warner
Backmatter
Metadaten
Titel
New Computational Paradigms
herausgegeben von
S. Barry Cooper
Benedikt Löwe
Andrea Sorbi
Copyright-Jahr
2008
Verlag
Springer New York
Electronic ISBN
978-0-387-68546-5
Print ISBN
978-0-387-36033-1
DOI
https://doi.org/10.1007/978-0-387-68546-5

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