Results 21  30
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68
From String Rewriting to Logical Metabolic Systems
 GRAMMATICAL MODELS OF MULTIAGENT SYSTEMS, GORDON AND BREACH SCIENCE PUBLISHERS
, 1997
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Commutation Problems on Sets of Words and Formal Power Series
, 2002
"... We study in this thesis several problems related to commutation on sets of words and on formal power series. We investigate the notion of semilinearity for formal power series in commuting variables, introducing two families of series  the semilinear and the bounded series  both natural generaliza ..."
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We study in this thesis several problems related to commutation on sets of words and on formal power series. We investigate the notion of semilinearity for formal power series in commuting variables, introducing two families of series  the semilinear and the bounded series  both natural generalizations of the semilinear languages, and we study their behaviour under rational operations, morphisms, Hadamard product, and difference. Turning to commutation on sets of words, we then study the notions of centralizer of a language  the largest set commuting with a language , of root and of primitive root of a set of words. We answer a question raised by Conway more than thirty years ago  asking whether or not the centralizer of any rational language is rational  in the case of periodic, binary, and ternary sets of words, as well as for rational ccodes, the most general results on this problem. We also prove that any code has a unique primitive root and that two codes commute if and only if they have the same primitive root, thus solving two conjectures of Ratoandromanana, 1989. Moreover, we prove that the commutation with an ccode X can be characterized similarly as in free monoids: a language commutes with X if and only if it is a union of powers of the primitive root of X.
Turing Oracle Machines, Online Computing, and Three Displacements in Computability Theory
, 2009
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The complexity of small universal Turing machines: a survey
, 2007
"... We survey some work concerned with small universal Turing machines, cellular automata, tag systems, and other simple models of computation. For example it has been an open question for some time as to whether the smallest known universal Turing machines of Minsky, Rogozhin, Baiocchi and Kudlek are e ..."
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We survey some work concerned with small universal Turing machines, cellular automata, tag systems, and other simple models of computation. For example it has been an open question for some time as to whether the smallest known universal Turing machines of Minsky, Rogozhin, Baiocchi and Kudlek are efficient (polynomial time) simulators of Turing machines. These are some of the most intuitively simple computational devices and previously the best known simulations were exponentially slow. We discuss recent work that shows that these machines are indeed efficient simulators. As a related result we also find that Rule 110, a wellknown elementary cellular automaton, is also efficiently universal. We also mention some old and new universal programsize results, including new small universal Turing machines and new weakly, and semiweakly, universal Turing machines. We then discuss some ideas for future work arising out of these, and other, results.
An Evolutionary Post Production System
 Advances in Learning Classifier Systems
, 2000
"... ed this by imposing an economic model based on two general principles, conservation of money and strong property rights, that together prevent these misallocations. Second, it appears likely that the representation language used by classiers is not computationally universal, nor even suf ciently ..."
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ed this by imposing an economic model based on two general principles, conservation of money and strong property rights, that together prevent these misallocations. Second, it appears likely that the representation language used by classiers is not computationally universal, nor even suf ciently powerful, when one restricts consideration to congurations that are dynamically stable[Bau96, LU99]. We address this representation problem by using a more powerful agent language. Our rst economic model, Hayek1, used simple agents, and because of the dynamic stability problem could only solve large BW problems when given intermediate reward for partial progress[Bau96]. Our last economic model, Hayek3, used agents that compute Sexpressions[BD00]. This model of computation was not Turingcomplete, and so the system could not produce a program capable of solving arbitrary instances. It did, however, produce systems capable of solving random instances with hundreds of blocks, unscr
A framework for reactive intelligence through agile componentbased behaviors
, 2003
"... This dissertation introduces PyPOSH, a reactive agent architecture with loadable behavioral modules based on Bryson’s ParallelRooted Ordered SlipStack Hierarchical action selection model. The framework utilizes a modular and objectoriented interface to behaviors built utilizing agile and componen ..."
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This dissertation introduces PyPOSH, a reactive agent architecture with loadable behavioral modules based on Bryson’s ParallelRooted Ordered SlipStack Hierarchical action selection model. The framework utilizes a modular and objectoriented interface to behaviors built utilizing agile and componentbased methods.
An Infinite Automaton Characterization of Double Exponential Time
"... Infinitestate automata are a new invention: they are automata that have an infinite number of states represented by words, transitions defined using rewriting, and with sets of initial and final states. Infinitestate automata have gained recent interest due to a remarkable result by Morvan and Sti ..."
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Infinitestate automata are a new invention: they are automata that have an infinite number of states represented by words, transitions defined using rewriting, and with sets of initial and final states. Infinitestate automata have gained recent interest due to a remarkable result by Morvan and Stirling, which shows that automata with transitions defined using rational rewriting precisely capture contextsensitive (NLINSPACE) languages. In this paper, we show that infinite automata defined using a form of multistack rewriting precisely defines double exponential time (more precisely, 2ETIME, the class of problems solvable in 2 2O(n) time). The salient aspect of this characterization is that the automata have no ostensible limits on time nor space, and neither direction of containment with respect to 2ETIME is obvious. In this sense, the result captures the complexity class qualitatively, by restricting the power of rewriting.
On the Universality of Post and Splicing Systems
 Biocomputing: Proceedings of the 1996 Pacific Symposium pages 288299. World Scientific Publishing Co
, 1996
"... In search for a universal splicing system, in this paper we present a Post system universal for the class of Post systems, and we discuss its translation into an extended splicing system with multiplicity. We also discuss the complexity of the resulting universal splicing system, comparing our resul ..."
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In search for a universal splicing system, in this paper we present a Post system universal for the class of Post systems, and we discuss its translation into an extended splicing system with multiplicity. We also discuss the complexity of the resulting universal splicing system, comparing our result with recent known results about the translation of universal Turing machines into splicing systems. 1 Introduction Since the possibility of molecular computing was shown by Adleman's pioneering work ([1]) which, in a test tube, experimentally solves a small instance of an NPcomplete problem, the theoretical formalization of such a new computing technology has been attracting much attention in computer science ([3][5][6][12][17]). One of the formal frameworks for molecular computations is the Tom Head's splicing system ( or H system ), which gives a theoretical foundation for computing based on DNA recombination. Tom Head's seminal work ([9]) on modeling DNA recombination as a splicing sys...
The Evolution of ModelTheoretic Frameworks in Linguistics
"... The varieties of mathematical basis for formalizing linguistic theories are more diverse than is commonly realized. For example, the later work of Zellig Harris might well suggest a formalization in terms of CATE ..."
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The varieties of mathematical basis for formalizing linguistic theories are more diverse than is commonly realized. For example, the later work of Zellig Harris might well suggest a formalization in terms of CATE
A natural axiomatization of Church’s thesis
, 2007
"... The Abstract State Machine Thesis asserts that every classical algorithm is behaviorally equivalent to an abstract state machine. This thesis has been shown to follow from three natural postulates about algorithmic computation. Here, we prove that augmenting those postulates with an additional requ ..."
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The Abstract State Machine Thesis asserts that every classical algorithm is behaviorally equivalent to an abstract state machine. This thesis has been shown to follow from three natural postulates about algorithmic computation. Here, we prove that augmenting those postulates with an additional requirement regarding basic operations implies Church’s Thesis, namely, that the only numeric functions that can be calculated by effective means are the recursive ones (which are the same, extensionally, as the Turingcomputable numeric functions). In particular, this gives a natural axiomatization of Church’s Thesis, as Gödel and others suggested may be possible.