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31
Deciding BisimulationLike Equivalences with FiniteState Processes
, 1999
"... We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many mo ..."
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Cited by 39 (14 self)
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We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many more classes of infinitestate systems. This yields a general method for proving decidability of bisimulationlike equivalences between infinitestate processes and finitestate ones. We apply this method to the class of PAD processes, which strictly subsumes PA and pushdown (PDA) processes, showing that a large class of bisimulationlike equivalences (including, e.g., strong and weak bisimilarity) is decidable between PAD and finitestate processes. On the other hand, we also demonstrate that no `reasonable' bisimulationlike equivalence is decidable between stateextended PA processes and finitestate ones. Furthermore, weak bisimilarity with finitestate processes is shown to be undecidable even for state...
Analysis of Adaptation and Environment
 Artificial Intelligence
, 1995
"... Designers often improve the performance of artifical agents by specializing them. We can make a rough, but useful distinction between specialization to a task and specialization to an environment. Specialization to an environment can be difficult to understand: it may be unclear on what properties o ..."
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Cited by 36 (3 self)
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Designers often improve the performance of artifical agents by specializing them. We can make a rough, but useful distinction between specialization to a task and specialization to an environment. Specialization to an environment can be difficult to understand: it may be unclear on what properties of the environment the agent depends, or in what manner it depends on each individual property. In this paper, I discuss a method for analyzing specialization into a series of conditional optimizations: formal transformations which, given some constraint on the environment, map mechanisms to more efficient mechanisms with equivalent behavior. I apply the technique to the analysis of the vision and control systems of a working robot system in dayto day use in our laboratory.
What is the philosophy of information
 Metaphilosophy
, 2002
"... Andre Gide once wrote that one does not discover new lands without consenting to ..."
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Cited by 31 (3 self)
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Andre Gide once wrote that one does not discover new lands without consenting to
Which Semantic Web?
, 2003
"... Through scenarios in the popular press and technical papers in the research literature, the promise of the Semantic Web has raised a number of different expectations. These expectations can be traced to three different perspectives on the Semantic Web. The Semantic Web is portrayed as: (1) a univers ..."
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Cited by 28 (0 self)
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Through scenarios in the popular press and technical papers in the research literature, the promise of the Semantic Web has raised a number of different expectations. These expectations can be traced to three different perspectives on the Semantic Web. The Semantic Web is portrayed as: (1) a universal library, to be readily accessed and used by humans in a variety of information use contexts; (2) the backdrop for the work of computational agents completing sophisticated activities on behalf of their human counterparts; and (3) a method for federating particular knowledge bases and databases to perform anticipated tasks for humans and their agents. Each of these perspectives has both theoretical and pragmatic entailments, and a wealth of past experiences to guide and temper our expectations. In this paper, we examine all three perspectives from rhetorical, theoretical, and pragmatic viewpoints with an eye toward possible outcomes as Semantic Web efforts move forward.
Some Complexity Results for Polynomial Ideals
, 1997
"... In this paper, we survey some of our new results on the complexity of a number of problems related to polynomial ideals. We consider multivariate polynomials over some ring, like the integers or the rationals. For instance, a polynomial ideal membership problem is a (w + 1)tuple P = ( f, g1, g2,.. ..."
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Cited by 16 (0 self)
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In this paper, we survey some of our new results on the complexity of a number of problems related to polynomial ideals. We consider multivariate polynomials over some ring, like the integers or the rationals. For instance, a polynomial ideal membership problem is a (w + 1)tuple P = ( f, g1, g2,..., gw) where f and the gi are multivariate polynomials, and the problem is to determine whether f is in the ideal generated by the gi. For polynomials over the integers or rationals, this problem is known to be exponential space complete. We discuss further complexity results for problems related to polynomial ideals, like the word and subword problems for commutative semigroups, a quantitative version of Hilbert’s Nullstellensatz in a complexity theoretic version, and problems concerning the computation of reduced polynomials and Gröbner bases.
Open problems in the philosophy of information
 Metaphilosophy
"... Abstract: The philosophy of information (PI) is a new area of research with its own field of investigation and methodology. This article, based on the Herbert A. Simon Lecture of Computing and Philosophy I gave at Carnegie Mellon University in 2001, analyses the eighteen principal open problems in P ..."
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Cited by 14 (1 self)
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Abstract: The philosophy of information (PI) is a new area of research with its own field of investigation and methodology. This article, based on the Herbert A. Simon Lecture of Computing and Philosophy I gave at Carnegie Mellon University in 2001, analyses the eighteen principal open problems in PI. Section 1 introduces the analysis by outlining Herbert Simon’s approach to PI. Section 2 discusses some methodological considerations about what counts as a good philosophical problem. The discussion centers on Hilbert’s famous analysis of the central problems in mathematics. The rest of the article is devoted to the eighteen problems. These are organized into five sections: problems in the analysis of the concept of information, in semantics, in the study of intelligence, in the relation between information and nature, and in the investigation of values.
An Algebraic Framework to Represent Finite State Machines in SingleLayer Recurrent Neural Networks
 Neural Computation
, 1995
"... In this paper we present an algebraic framework to represent finite state machines (FSMs) in singlelayer recurrent neural networks (SLRNNs), which unifies and generalizes some of the previous proposals. This framework is based on the formulation of both the state transition function and the output ..."
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Cited by 13 (0 self)
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In this paper we present an algebraic framework to represent finite state machines (FSMs) in singlelayer recurrent neural networks (SLRNNs), which unifies and generalizes some of the previous proposals. This framework is based on the formulation of both the state transition function and the output function of a FSM as a linear system of equations, and it permits an analytical explanation of the representational capabilities of firstorder and higherorder SLRNNs. The framework can be used to insert symbolic knowledge in RNNs prior to learning from examples and to keep this knowledge while training the network. This approach is valid for a wide range of activation functions, whenever some stability conditions are met. The framework has already been used in practice in a hybrid method for grammatical inference reported elsewhere (Sanfeliu and Alquezar, 1994). 1 Introduction The representation of finitestate machines (FSMs) in recurrent neural networks (RNNs) has attracted the attention...
Continuousspace model of computation is Turing universal
 Critical Technologies for the Future of Computing, Proceedings of SPIE vol. 4109
, 2000
"... Our model of computation (theoretical machine) was designed for the analysis of analog Fourier optical processors, its basic data unit being a continuous image of unbounded resolution. In this paper, we demonstrate the universality of our machine by presenting a framework for arbitrary Turing machin ..."
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Cited by 11 (4 self)
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Our model of computation (theoretical machine) was designed for the analysis of analog Fourier optical processors, its basic data unit being a continuous image of unbounded resolution. In this paper, we demonstrate the universality of our machine by presenting a framework for arbitrary Turing machine simulation. Computational complexity benets are also demonstrated by providing a O(log 2 n) algorithm for a search problem that has a lower bound of n 1 on a Turing machine.
On the Expressiveness and Decidability of HigherOrder Process Calculi
, 2008
"... In higherorder process calculi the values exchanged in communications may contain processes. A core calculus of higherorder concurrency is studied; it has only the operators necessary to express higherorder communications: input prefix, process output, and parallel composition. By exhibiting a ne ..."
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Cited by 11 (5 self)
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In higherorder process calculi the values exchanged in communications may contain processes. A core calculus of higherorder concurrency is studied; it has only the operators necessary to express higherorder communications: input prefix, process output, and parallel composition. By exhibiting a nearly deterministic encoding of Minsky Machines, the calculus is shown to be Turing Complete and therefore its termination problem is undecidable. Strong bisimilarity, however, is proved to be decidable. Further, the main forms of strong bisimilarity for higherorder processes (higherorder bisimilarity, context bisimilarity, normal bisimilarity, barbed congruence) coincide. They also coincide with their asynchronous versions. A sound and complete axiomatization of bisimilarity is given. Finally, bisimilarity is shown to become undecidable if at least four static (i.e., toplevel) restrictions are added to the calculus.