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Query Reasoning on Trees with Types, Interleaving, and Counting
 PROCEEDINGS OF THE TWENTYSECOND INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE
, 2011
"... A major challenge of query language design is the combination of expressivity with effective static analyses such as query containment. In the setting of XML, documents are seen as finite trees, whose structure may additionally be constrained by type constraints such as those described by an XML sch ..."
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Cited by 4 (4 self)
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A major challenge of query language design is the combination of expressivity with effective static analyses such as query containment. In the setting of XML, documents are seen as finite trees, whose structure may additionally be constrained by type constraints such as those described by an XML schema. We consider the problem of query containment in the presence of type constraints for a class of regular path queries extended with counting and interleaving operators. The counting operator restricts the number of occurrences of children nodes satisfying a given logical property. The interleaving operator provides a succinct notation for describing the absence of order between nodes satisfying a logical property. We provide a logicbased framework supporting these operators, which can be used to solve common query reasoning problems such as satisfiability and containment of queries in exponential time.
Efficiently Deciding µcalculus with Converse over Finite Trees
, 2013
"... We present a sound and complete satisfiabilitytesting algorithm and its effective implementation for an alternationfree modal µcalculus with converse, where formulas are cyclefree, and which is interpreted over finite ordered trees. The time complexity of the satisfiabilitytesting algorithm is ..."
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Cited by 4 (2 self)
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We present a sound and complete satisfiabilitytesting algorithm and its effective implementation for an alternationfree modal µcalculus with converse, where formulas are cyclefree, and which is interpreted over finite ordered trees. The time complexity of the satisfiabilitytesting algorithm is 2 O(n) in terms of formula size n. The algorithm is implemented using symbolic techniques (BDD). We present crucial implementation techniques and heuristics that we used to make the algorithm as fast as possible in practice. Our implementation is available online, and can be used to solve logical formulas of practically significant size.
Deciding Twigdefinability of Node Selecting Tree Automata
, 2012
"... Node selecting tree automata (NSTAs) constitute a general formalism defining unary queries over trees. Basically, a node is selected by an NSTA when it is visited in a selecting state during an accepting run. We consider twig patterns as an abstraction of XPath. Since the queries definable by NSTAs ..."
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Cited by 1 (1 self)
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Node selecting tree automata (NSTAs) constitute a general formalism defining unary queries over trees. Basically, a node is selected by an NSTA when it is visited in a selecting state during an accepting run. We consider twig patterns as an abstraction of XPath. Since the queries definable by NSTAs form a strict superset of twigdefinable queries, we study the complexity of the problem to decide whether the query by a given NSTA is twigdefinable. In particular, we obtain that the latter problem is EXPTIMEcomplete. In addition, we show that it is also EXPTIMEcomplete to decide whether the query by a given NSTA is definable by a node selecting string automaton.
ViewBased TreeLanguage Rewritings for XML
"... Abstract. We study query rewriting using views (QRV) for XML. Our queries and views are regular tree languages (RTLs) represented by tree automata over marked alphabets, where the markers serve as "node selectors". We formally define query rewriting using views for RTLs and give an automa ..."
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Abstract. We study query rewriting using views (QRV) for XML. Our queries and views are regular tree languages (RTLs) represented by tree automata over marked alphabets, where the markers serve as "node selectors". We formally define query rewriting using views for RTLs and give an automatabased algorithm to compute the maximally contained rewriting. The formalism we use is equal in power with Monadic Second Order (MSO) logic, and our algorithm for computing QRV is the first to target this expressive class. Furthermore we prove a tight lower bound, thus showing that our algorithm is optimal. Another strength of our automatabased approach is that we are able to cast computing QRV into executing a sequence of intuitive operations on automata, thus rendering our approach practical as it can be easily implemented utilizing offtheshelf automata toolboxes. Finally, we generalize our framework to account for more complex queries in the spirit of the FOR clause in XQuery. For this generalization as well, we give an optimal algorithm for computing the maximally contained rewriting of queries using views.
A Core Calculus for XQuery 3.0
"... Abstract. XML processing languages can be classified according to whether they extract XML data by paths or pattern matching. In the former category one finds XQuery, in the latter XDuce and CDuce. The strengths of one category correspond to the weaknesses of the other. In this work, we propose to b ..."
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Abstract. XML processing languages can be classified according to whether they extract XML data by paths or pattern matching. In the former category one finds XQuery, in the latter XDuce and CDuce. The strengths of one category correspond to the weaknesses of the other. In this work, we propose to bridge the gap between two of these languages: XQuery and CDuce. We do it by extending CDuce so as it can be seen as a succinct core λcalculus that captures XQuery 3.0 programs. The extensions we consider essentially allow CDuce to implement by pattern matching XPathlike navigation expressions and to precisely type them. The encoding of XQuery 3.0 into the extension of CDuce provides a formal semantics and a sound static type system for XQuery 3.0 programs. 1.
Query Reasoning on Trees with Types, Interleaving, and Counting
, 2011
"... HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte p ..."
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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.