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48
Efficient inclusion checking for deterministic tree automata and xml schemas
, 2007
"... Abstract. We present a new algorithm for testing language inclusion L(A) ⊆ L(B) between tree automata in time O(A  ∗ B) where B is deterministic. We extend this algorithm for testing inclusion between automata for unranked trees A and deterministic DTDs D in time O(A∗ Σ  ∗ D). No previo ..."
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Abstract. We present a new algorithm for testing language inclusion L(A) ⊆ L(B) between tree automata in time O(A  ∗ B) where B is deterministic. We extend this algorithm for testing inclusion between automata for unranked trees A and deterministic DTDs D in time O(A∗ Σ  ∗ D). No previous algorithms with these complexities exist. inria00192329, version 6 5 Mar 2009 1
Unification in a Description Logic with Transitive Closure of Roles
, 2001
"... Unification of concept descriptions was introduced by Baader and Narendran as a tool for detecting redundancies in knowledge bases. It was shown that unification in the small description logic FL 0 , which allows for conjunction, value restriction, and the top concept only, is already ExpTime comple ..."
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Cited by 14 (5 self)
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Unification of concept descriptions was introduced by Baader and Narendran as a tool for detecting redundancies in knowledge bases. It was shown that unification in the small description logic FL 0 , which allows for conjunction, value restriction, and the top concept only, is already ExpTime complete. The present paper shows that the complexity does not increase if one additionally allows for composition, union, and transitive closure of roles. It also shows that matching (which is polynomial in FL 0 ) is PSpacecomplete in the extended description logic.
Deciding H1 by Resolution
, 2005
"... Nielson, Nielson and Seidl’s class H1 is a decidable class of firstorder Horn clause sets, describing strongly regular relations. We give another proof of decidability, and of the regularity of the defined languages, based on fairly standard automated deduction techniques. ..."
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Cited by 12 (3 self)
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Nielson, Nielson and Seidl’s class H1 is a decidable class of firstorder Horn clause sets, describing strongly regular relations. We give another proof of decidability, and of the regularity of the defined languages, based on fairly standard automated deduction techniques.
Rigid Tree Automata
, 2008
"... We introduce the class of Rigid Tree Automata (RTA), an extension of standard bottomup automata on ranked trees with distinguished states called rigid. Rigid states define a restriction on the computation of RTA on trees: two subtrees reaching the same rigid state in a run must be equal. RTA are ab ..."
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Cited by 10 (1 self)
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We introduce the class of Rigid Tree Automata (RTA), an extension of standard bottomup automata on ranked trees with distinguished states called rigid. Rigid states define a restriction on the computation of RTA on trees: two subtrees reaching the same rigid state in a run must be equal. RTA are able to perform local and global tests of equality between subtrees, nonlinear tree pattern matching, and restricted disequality tests as well. Properties like determinism, pumping lemma, Boolean closure, and several decision problems are studied in detail. In particular, the emptiness problem is shown decidable in linear time for RTA whereas membership of a given tree to the language of a given RTA is NPcomplete. Our main result is that is decidable whether a given tree belongs to the rewrite closure of a RTA language under a restricted family of term rewriting systems, whereas this closure is not a RTA language. This result, one of the first on rewrite closure of languages of tree automata with constraints, is enabling the extension of model checking procedures based on finite tree automata techniques. Finally, a comparison of RTA with several classes of tree automata with local and global equality tests, and with dag automata is also provided.
Unification in extensions of shallow equational theories
 REWRITING TECHNIQUES AND APPLICATIONS, 9TH INTERNATIONAL CONFERENCE, RTA98', VOL. 1379 OF LNCS
, 1998
"... We show that unification in certain extensions of shallow equational theories is decidable. Our extensions generalize the known classes of shallow or standard equational theories. In order to prove decidability of unification in the extensions, a class of Horn clause sets called sorted shallow equa ..."
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Cited by 10 (2 self)
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We show that unification in certain extensions of shallow equational theories is decidable. Our extensions generalize the known classes of shallow or standard equational theories. In order to prove decidability of unification in the extensions, a class of Horn clause sets called sorted shallow equational theories is introduced. This class is a natural extension of tree automata with equality constraints between brother subterms as well as shallow sort theories. We show that saturation under sorted superposition is effective on sorted shallow equational theories. So called semilinear equational theories can be e ectively transformed into equivalent sorted shallow equational theories and generalize the classes of shallow and standard equational theories.
The Decidability of Simultaneous Rigid EUnification with One Variable
 REWRITING TECHNIQUES AND APPLICATIONS
, 1997
"... We show that simultaneous rigid Eunification, or SREU for short, is decidable and in fact EXPTIMEcomplete in the case of one variable. This result implies that the ... fragment of intuitionistic logic with equality is decidable. Together with a previous result regarding the undecidability of the ..."
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Cited by 10 (10 self)
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We show that simultaneous rigid Eunification, or SREU for short, is decidable and in fact EXPTIMEcomplete in the case of one variable. This result implies that the ... fragment of intuitionistic logic with equality is decidable. Together with a previous result regarding the undecidability of the 99fragment, we obtain a complete classification of decidability of the prenex fragment of intuitionistic logic with equality, in terms of the quantifier prefix. It is also proved that SREU with one variable and a constant bound on the number of rigid equations is Pcomplete.
Microarchitecture Modeling for DesignSpace Exploration DesignSpace Exploration
, 2004
"... To identify the best processor designs, designers explore a vast design space. To assess the quality of candidate designs, designers construct and use simulators. Unfortunately, simulator construction is a bottleneck in this designspace exploration because existing simulator construction methodolog ..."
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Cited by 10 (2 self)
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To identify the best processor designs, designers explore a vast design space. To assess the quality of candidate designs, designers construct and use simulators. Unfortunately, simulator construction is a bottleneck in this designspace exploration because existing simulator construction methodologies lead to long simulator development times. This bottleneck limits exploration to a small set of designs, potentially diminishing quality of the final design.
Paths vs. Trees in Setbased Program Analysis
 PROCEEDINGS OF POPL'00: PRINCIPLES OF PROGRAMMING LANGUAGES
, 2000
"... Setbased analysis of logic programs provides an accurate method for descriptive typechecking of logic programs. The key idea of this method is to upper approximate the least model of the program by a regular set of trees. In 1991, Frühwirth, Shapiro, Vardi and Yardeni raised the question whether i ..."
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Cited by 9 (3 self)
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Setbased analysis of logic programs provides an accurate method for descriptive typechecking of logic programs. The key idea of this method is to upper approximate the least model of the program by a regular set of trees. In 1991, Frühwirth, Shapiro, Vardi and Yardeni raised the question whether it can be more efficient to use the domain of sets of paths instead, i.e., to approximate the least model by a regular set of words. We answer the question negatively by showing that typechecking for pathbased analysis is as hard as the setbased one, that is DEXPTIMEcomplete. This result has consequences also in the areas of set constraints, automata theory and model checking.
Directional Type Checking for Logic Programs: Beyond Discriminative Types
 In Proc. of ESOP 2000
, 2000
"... Directional types form a type system for logic programs which is based on the view of a predicate as a directional procedure which, when applied to a tuple of input terms, generates a tuple of output terms. It is known that directionaltype checking wrt. arbitrary types is undecidable; several autho ..."
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Cited by 8 (1 self)
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Directional types form a type system for logic programs which is based on the view of a predicate as a directional procedure which, when applied to a tuple of input terms, generates a tuple of output terms. It is known that directionaltype checking wrt. arbitrary types is undecidable; several authors proved decidability of the problem wrt. discriminative regular types. In this paper, using techniques based on tree automata, we show that directionaltype checking for logic programs wrt. general regular types is DEXPTIMEcomplete and fixedparameter linear. The letter result shows that despite the exponential lower bound, the type system might be usable in practice.