Anne-Cécile Caron

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We deene a new class of tree automata which generalizes both the encompassment au-tomata of 3] and the automata with tests between brothers of 2]. We give a pumping lemma for these automata, which implies that the emptiness of the corresponding language is de-cidable. Then, we show how to decide emptiness by means of a "cleaning" algorithm, which leads to(More)
We consider semistructured data as rooted edge-labeled directed graphs, and path inclusion constraints on these graphs. In this paper, we show that we can extract from a finite datum D a finite set C f (D) of word inclusions, which implies exactly every word inclusion satisfied by D. Then, we give a new decision algorithm for the implication problem of a(More)
In this paper, we revisit the view based security framework for XML without imposing any of the previously considered restrictions on the class of queries, the class of DTDs, and the type of annotations used to define the view. First, we show that the full class of Regular XPath queries is closed under query rewriting. Next, we address the problem of(More)
We consider in this paper rooted labeled directed graphs as models for semistructured data. A path inclusion constraint, in such graphs, is an expression p q where p and q are regular expressions over the alphabet of labels. An path inclusion constraint p q is satisfied by a rooted labeled directed graph if the set of nodes reached, from the root, by the(More)
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We investigate the complexity of earliest query answering for n-ary node selection queries defined by streaming tree automata (STAs). We elaborate an algorithm that selects query answers upon reception of the shortest relevant prefix of the input tree on the stream. In general, deciding if a prefix is sufficient for the selection of a n-tuple is(More)