Proceedings 17th Annual IEEE Symposium on Logic in Computer Science

22-25 July 2002

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  • Proceedings 17th Annual IEEE Symposium on Logic in Computer Science

    Publication Year: 2002
    Request permission for commercial reuse | PDF file iconPDF (350 KB)
    Freely Available from IEEE
  • Little engines of proof

    Publication Year: 2002
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (239 KB)

    Summary form only given. The automated construction of mathematical proof is a basic activity in computing. Since the dawn of the field of automated reasoning, there have been two divergent schools of thought. One school, best represented by Alan Robinson's resolution method, is based on simple uniform proof search procedures guided by heuristics. The other school, pioneered by Hao Wang, argues fo... View full abstract»

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  • Semantic subtyping

    Publication Year: 2002, Page(s):137 - 146
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (410 KB)

    Usually subtyping relations are defined either syntactically by a formal system or semantically by an interpretation of types in an untyped denotational model. In this paper we show how to define a subtyping relation semantically, for a language whose operational semantics is driven by types; we consider a rich type algebra, with product, arrow, recursive, intersection, union and complement types.... View full abstract»

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  • Dense real-time games

    Publication Year: 2002, Page(s):167 - 176
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (414 KB) | HTML iconHTML

    The rapid development of complex and safety-critical systems requires the use of reliable verification methods and tools for system design (synthesis). Many systems of interest are reactive, in the sense that their behavior depends on the interaction with the environment. A natural framework to model them is a two-player game: the system versus the environment. In this context, the central problem... View full abstract»

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  • Temporal logic with forgettable past

    Publication Year: 2002, Page(s):383 - 392
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (459 KB) | HTML iconHTML

    We investigate NLTL, a linear-time temporal logic with forgettable past. NLTL can be exponentially more succinct than LTL+Past (which in turn can be more succinct than LTL). We study satisfiability and model checking for NLTL and provide optimal automata-theoretic algorithms for these EXPSPACE-complete problems. View full abstract»

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  • Decidable and undecidable fragments of first-order branching temporal logics

    Publication Year: 2002, Page(s):393 - 402
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (433 KB) | HTML iconHTML

    In this paper we analyze the decision problem for fragments of first-order extensions of branching time temporal logics such as computational tree logics CTL and CTL* or Prior's Ockhamist logic of historical necessity. On the one hand, we show that the one-variable fragments of logics like first-order CTL*-such as the product of propositional CTL* with simple propositional modal logic S5, or even ... View full abstract»

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  • The metric analogue of weak bisimulation for probabilistic processes

    Publication Year: 2002, Page(s):413 - 422
    Cited by:  Papers (39)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (379 KB) | HTML iconHTML

    We observe that equivalence is not a robust concept in the presence of numerical information - such as probabilities-in the model. We develop a metric analogue of weak bisimulation in the spirit of our earlier work on metric analogues for strong bisimulation. We give a fixed point characterization of the metric. This makes available conductive reasoning principles and allows us to prove metric ana... View full abstract»

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  • Author index

    Publication Year: 2002, Page(s): 457
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    Freely Available from IEEE
  • Description logics: foundations for class-based knowledge representation

    Publication Year: 2002, Page(s):359 - 370
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (371 KB) | HTML iconHTML

    Class-based languages express knowledge in terms of objects and classes, and have inspired a huge number of formalisms in computer science. Description logics forma family of both class-based and logic-based knowledge representation languages which allow for modeling an application domain in terms of objects, classes and relationships between classes, and for reasoning about them. This paper prese... View full abstract»

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  • Calibrating computational feasibility by abstraction rank

    Publication Year: 2002, Page(s):345 - 354
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (499 KB) | HTML iconHTML

    We characterize computationally the functions provable in second order logic with set existence restricted to natural classes of first order formulas. A classification of first-order set-existence by implicational rank yields a natural hierarchy of complexity classes within the class of Kalmar-elementary functions: The functions over {0, 1}* constructively provable using set existence for formulas... View full abstract»

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  • The proof complexity of linear algebra

    Publication Year: 2002, Page(s):335 - 344
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB) | HTML iconHTML

    We introduce three formal theories of increasing strength for linear algebra in order to study the complexity of the concepts needed to prove the basic theorems of the subject. We give what is apparently the first feasible proofs of the Cayley-Hamilton theorem and other properties of the determinant, and study the propositional proof complexity of matrix identities. View full abstract»

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  • Unsatisfiable random formulas are hard to certify

    Publication Year: 2002, Page(s):325 - 334
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (379 KB) | HTML iconHTML

    We prove that every property of 3CNF formulas that implies unsatisfiability and is expressible in Datalog has asymptotic probability zero when formulas are randomly generated by taking 6n non-trivial clauses of exactly three literals uniformly and independently. Our result is a consequence of designing a winning strategy for Duplicator in the existential k-pebble game on the structure that encodes... View full abstract»

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  • Monadic queries over tree-structured data

    Publication Year: 2002, Page(s):189 - 202
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (383 KB)

    Monadic query languages over trees currently receive considerable interest in the database community, as the problem of selecting nodes from a tree is the most basic and widespread database query problem in the context of XML. Partly a survey of recent work done by the authors and their group on logical query languages for this problem and their expressiveness, this paper provides a number of new ... View full abstract»

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  • Games on graphs and sequentially realizable functionals. Extended abstract

    Publication Year: 2002, Page(s):257 - 264
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (327 KB) | HTML iconHTML

    We present a new category of games on graphs and derive from it a model for Intuitionistic Linear Logic. Our category has the computational flavour of concrete data structures but embeds fully and faithfully in an abstract games model. It differs markedly from the usual Intuitionistic Linear Logic setting for sequential algorithms. However, we show that with a natural exponential we obtain a model... View full abstract»

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  • Complete problems for dynamic complexity classes

    Publication Year: 2002, Page(s):313 - 322
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    We present the first complete problems for dynamic complexity classes including the classes Dyn-FO and Dyn-ThC0, the dynamic classes corresponding to relational calculus and (polynomially bounded) SQL, respectively. The first problem we show complete for Dyn-FO is a single-step version of the circuit value problem (SSCV). Of independent interest, our construction also produces a first-o... View full abstract»

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  • Efficient type inference for record concatenation and subtyping

    Publication Year: 2002, Page(s):125 - 136
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (355 KB) | HTML iconHTML

    Record concatenation, multiple inheritance, and multiple-object cloning are closely related and part of various language designs. For example, in Cardelli's untyped Obliq language, a new object can be constructed from several existing objects by cloning followed by concatenation; an error is given in case of field name conflicts. Type systems for record concatenation have been studied by M. Wand (... View full abstract»

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  • Computing reachability relations in timed automata

    Publication Year: 2002, Page(s):177 - 186
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (451 KB) | HTML iconHTML

    We give an algorithmic calculus of the reachability relations on clock values defined by timed automata. Our approach is a modular one, by computing unions, compositions and reflexive-transitive closure (star) of "atomic" relations. The essential tool is a new representation technique for n-clock relations - the 2n-automata - and our strategy is to show the closure under union, composition and sta... View full abstract»

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  • Observational equivalence of 3rd-order Idealized Algol is decidable

    Publication Year: 2002, Page(s):245 - 256
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (451 KB) | HTML iconHTML

    We prove that observational equivalence of 3rd-order finitary Idealized Algol (IA) is decidable using Game Semantics. By modelling state explicitly in our games, we show that the denotation of a term M of this fragment of IA (built up from finite base types) is a compactly innocent strategy-with-state i.e. the strategy is generated by a finite view function fM. Given any such fM View full abstract»

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  • Deciding confluence of certain term rewriting systems in polynomial time

    Publication Year: 2002, Page(s):447 - 457
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB) | HTML iconHTML

    We present a polynomial time algorithm for deciding confluence of ground term rewrite systems. We generalize the decision procedure to get a polynomial time algorithm, assuming that the maximum arity of a symbol in the signature is a constant, for deciding confluence of rewrite systems where each rule contains a shallow linear term on one side and a ground term on the other. The existence of a pol... View full abstract»

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  • Domain theory and differential calculus (functions of one variable)

    Publication Year: 2002, Page(s):277 - 286
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB) | HTML iconHTML

    A data-type for differential calculus is introduced, which is based on domain theory. We define the integral and also the derivative of a Scott continuous function on the domain of intervals, and present a domain-theoretic generalization of the fundamental theorem of calculus. We then construct a domain for differentiable real valued functions of a real variable. The set of classical C1... View full abstract»

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  • The powerdomain of indexed valuations

    Publication Year: 2002, Page(s):299 - 308
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (378 KB) | HTML iconHTML

    This paper is about combining nondeterminism and probabilities. We study this phenomenon from a domain theoretic point of view. In domain theory, nondeterminism is modeled using the notion of powerdomain, while probability is modeled using the powerdomain of valuations. Those two functors do not combine well, as they are. We define the notion of powerdomain of indexed valuations, which can be comb... View full abstract»

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  • Semantics and logic of object calculi

    Publication Year: 2002, Page(s):113 - 122
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (391 KB) | HTML iconHTML

    The main contribution of this paper is a formal characterization of recursive object specifications based on a denotational untyped semantics of the object calculus and the discussion of existence of those (recursive) specifications. The semantics is then applied to prove soundness of a programming logic for the object calculus and to suggest possible extensions. For the purposes of this discussio... View full abstract»

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  • A syntactic approach to foundational proof-carrying code

    Publication Year: 2002, Page(s):89 - 100
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB) | HTML iconHTML

    Proof-carrying code (PCC) is a general framework for verifying the safety properties of machine-language programs. PCC proofs are usually written in a logic extended with language-specific typing rules. In foundational proof-carrying code (FPCC), on the other hand, proofs are constructed and verified using strictly the foundations of mathematical logic, with no type-specific axioms. FPCC is more f... View full abstract»

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  • Some results on automatic structures

    Publication Year: 2002, Page(s):235 - 242
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (353 KB) | HTML iconHTML

    We study the class of countable structures which can be presented by synchronous finite automata. We reduce the problem of existence of an automatic presentation of a structure to that for a graph. We exhibit a series of properties of automatic equivalence structures, linearly ordered sets and permutation structures. These serve as a first step in producing practical descriptions of some automatic... View full abstract»

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  • Linearity in process languages

    Publication Year: 2002, Page(s):433 - 444
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (449 KB)

    The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open-map bisimulation, in which a range of process operations can be expressed. An operational semantics is provided... View full abstract»

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