Displaying similar documents to “On Core XPath with Inflationary Fixed Points”

Topologies, Continuity and Bisimulations

J. M. Davoren (2010)

RAIRO - Theoretical Informatics and Applications

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The notion of a is of basic importance in many areas of computation theory and logic. Of late, it has come to take a particular significance in work on the formal analysis and verification of , where system properties are expressible by formulas of the modal -calculus or weaker temporal logics. Our purpose here is to give an analysis of the concept of bisimulation, starting with the observation that the zig-zag conditions are suggestive of some form of continuity. We give a topological...

Inf-datalog, Modal Logic and Complexities

Eugénie Foustoucos, Irène Guessarian (2007)

RAIRO - Theoretical Informatics and Applications

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Inf-Datalog extends the usual least fixpoint semantics of Datalog with greatest fixpoint semantics: we defined inf-Datalog and characterized the expressive power of various fragments of inf-Datalog in [CITE]. In the present paper, we study the complexity of query evaluation on finite models for (various fragments of) inf-Datalog. We deduce a unified and elementary proof that global model-checking ( computing all nodes satisfying a formula in a given structure) has 1. quadratic...

A Note on Negative Tagging for Least Fixed-Point Formulae

Dilian Gurov, Bruce Kapron (2010)

RAIRO - Theoretical Informatics and Applications

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Proof systems with sequents of the form ⊢ Φ for proving validity of a propositional modal -calculus formula Φ over a set of states in a given model usually handle fixed-point formulae through unfolding, thus allowing such formulae to reappear in a proof. Tagging is a technique originated by Winskel for annotating fixed-point formulae with information about the proof states at which these are unfolded. This information is used later in the proof to avoid unnecessary unfolding,...

Regularity of languages defined by formal series with isolated cut point

Alberto Bertoni, Maria Paola Bianchi, Flavi D’Alessandro (2012)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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Let  = { ∈  | ()  } be the language recognized by a formal series :  → ℝ with isolated cut point . We provide new conditions that guarantee the regularity of the language in the case that is rational or is a Hadamard quotient of rational series. Moreover the decidability property of such conditions is investigated.

Denotational aspects of untyped normalization by evaluation

Andrzej Filinski, Henning Korsholm Rohde (2010)

RAIRO - Theoretical Informatics and Applications

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We show that the standard normalization-by-evaluation construction for the simply-typed -calculus has a natural counterpart for the untyped -calculus, with the central type-indexed logical relation replaced by a “recursively defined” , in the style of Pitts. In fact, the construction can be seen as generalizing a computational-adequacy argument for an untyped, call-by-name language to normalization instead of evaluation.In the untyped setting, not all terms have normal forms,...

Algebraic and graph-theoretic properties of infinite -posets

Zoltán Ésik, Zoltán L. Németh (2010)

RAIRO - Theoretical Informatics and Applications

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A -labeled -poset is an (at most) countable set, labeled in the set , equipped with partial orders. The collection of all -labeled -posets is naturally equipped with binary product operations and -ary product operations. Moreover, the -ary product operations give rise to -power operations. We show that those -labeled -posets that can be generated from the singletons by the binary and -ary product operations form the free algebra on in a variety axiomatizable...

Pointwise constrained radially increasing minimizers in the quasi-scalar calculus of variations

Luís Balsa Bicho, António Ornelas (2014)

ESAIM: Control, Optimisation and Calculus of Variations

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We prove of vector minimizers () =  (||) to multiple integrals ∫ ((), |()|)  on a  ⊂ ℝ, among the Sobolev functions (·) in + (, ℝ), using a  : ℝ×ℝ → [0,∞] with (·) and . Besides such basic hypotheses, (·,·) is assumed to satisfy also...

Integers in number systems with positive and negative quadratic Pisot base

Z. Masáková, T. Vávra (2014)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We consider numeration systems with base and − , for quadratic Pisot numbers and focus on comparing the combinatorial structure of the sets Z and Z of numbers with integer expansion in base , resp. − . Our main result is the comparison of languages of infinite words and coding the ordering of distances between consecutive - and (− )-integers. It turns out that for a class of roots of − − , the languages coincide, while for other...

Encoding FIX in Object Calculi

Roy L. Crole (2010)

RAIRO - Theoretical Informatics and Applications

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We show that the type theory introduced by Crole and Pitts [3] can be encoded in variants of Abadi and Cardelli's object calculi. More precisely, we show that the type theory presented with judgements of both equality and operational reduction can be translated into object calculi, and the translation proved sound. The translations we give can be seen as using object calculi as a metalanguge within which can be represented; an analogy can be drawn with Martin Löf's Theory of Arities...

Easy lambda-terms are not always simple

Alberto Carraro, Antonino Salibra (2012)

RAIRO - Theoretical Informatics and Applications

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A closed -term is if, for any other closed term , the lambda theory generated by  =  is consistent. Recently, it has been introduced a general technique to prove the easiness of -terms through the semantical notion of simple easiness. Simple easiness implies easiness and allows to prove consistency results construction of suitable filter models of -calculus living in the category of complete partial orderings: given ...

Closure properties of hyper-minimized automata

Andrzej Szepietowski (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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Two deterministic finite automata are almost equivalent if they disagree in acceptance only for finitely many inputs. An automaton is hyper-minimized if no automaton with fewer states is almost equivalent to . A regular language is canonical if the minimal automaton accepting is hyper-minimized. The asymptotic state complexity () of a regular language is the number of states of a hyper-minimized automaton for a language finitely different from . In this paper we show...

Easy lambda-terms are not always simple

Alberto Carraro, Antonino Salibra (2012)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Similarity:

A closed -term is if, for any other closed term , the lambda theory generated by  =  is consistent. Recently, it has been introduced a general technique to prove the easiness of -terms through the semantical notion of simple easiness. Simple easiness implies easiness and allows to prove consistency results construction of suitable filter models of -calculus living in the category of complete partial orderings: given a simple easy term and an arbitrary closed term , it is possible to...