Everardo Bárcenas

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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(More)
We introduce a logical foundation to reason on tree structures with constraints on the number of node occurrences. Related formalisms are limited to express occurrence constraints on particular tree regions, as for instance the children of a given node. By contrast, the logic introduced in the present work can concisely express numerical bounds on any(More)
We study the analysis problem of XPath expressions with counting constraints. Such expressions are commonly used in document transformations or programs in which they select portions of documents subject to transformations. We explore how recent results on the static analysis of navigational aspects of XPath can be extended to counting constraints. The(More)
We propose a tree logic capable of expressing simple cardi-nality constraints on the number of nodes selected by an arbitrarily deep regular path with backward navigation. Specifically , a sublogic of the alternation-free µ−calculus with converse for finite trees is extended with a counting operator in order to reason on the cardinality of node sets. Also,(More)
Regular tree grammars and regular path expressions constitute core constructs widely used in programming languages and type systems. Nevertheless , there has been little research so far on reasoning frameworks for path expressions where node cardinality constraints occur along a path in a tree. We present a logic capable of expressing deep counting along(More)
Regular tree grammars and regular path expressions constitute core constructs widely used in programming languages and type systems. Nevertheless , there has been little research so far on frameworks for reasoning about path expressions where node cardinality constraints occur along a path in a tree. We present a logic capable of expressing deep counting(More)