Conference Paper

XML Schema, Tree Logic and Sheaves Automata.

DOI: 10.1007/3-540-44881-0_18 Conference: Rewriting Techniques and Applications, 14th International Conference, RTA 2003, Valencia, Spain, June 9-11, 2003, Proceedings
Source: DBLP

ABSTRACT XML documents may be roughly described as unranked, ordered trees and it is therefore natural to use tree automata to process or validate them. This idea has already been successfully applied in the context of Document Type Defi- nition (DTD), the simplest standard for defining document va lidity, but additional work is needed to take into account XML Schema, a more advanced standard, for which regular tree automata are not satisfactory. In thi s paper, we introduce Sheaves Logic (SL), a new tree logic that extends the syntax of the — recursion- free fragment of — W3C XML Schema Definition Language (WXS). Then we define a new class of automata for unranked trees that provide s decision proce- dures for the basic questions about SL: model-checking; satisfiability; entailment. The same class of automata is also used to answer basic questions about WXS, in- cluding recursive schemas: decidability of type-checking documents; testing the emptiness of schemas; testing that a schema subsumes another one.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The structure of an XML document can be optionally specified by means of XML Schema, thus enabling the exploitation of structural information for efficient document handling. Upon schema evolution, or when exchanging documents among different collections exploiting related but not identical schemas, the need may arise of adapting a document, known to be valid for a given schema S, to a target schema S'. The adaptation may require knowledge of the element semantics and cannot always be automatically derived. In this paper, we present an automata-based method for the static analysis of user-defined XML document adaptations, expressed as sequences of XQuery Update update primitives. The key feature of the method is the use of an automatic inference method for extracting the type, expressed as a Hedge Automaton, of a sequence of document updates. The type is computed starting from the original schema S and from rewriting rules that formally define the operational semantics of a sequence of document updates. Type inclusion can then be used as conformance test w.r.t. the type extracted from the target schema S'.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider the framework of regular hedge model checking where configurations are represented by trees of arbitrary arities, sets of configurations are represented by regular hedge automata, and the dynamic of a system is modeled by a term rewriting system. We consider the problem of computing the transitive closure R ∗(L) of a hedge automaton L and a (not necessarily structure preserving) term rewriting system R. This construction is not possible in general. Therefore, we present a semi-algorithm that computes, in case of termination, an over-approximation of this reachability set. We show that our procedure computes the exact reachability set in many practical applications. We have successfully applied our technique to compute transitive closures for some mutual exclusion protocols defined on arbitrary width tree topologies, as well as for two interesting XML applications.
    IJCCBS. 01/2012; 3:132-150.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 logic-based framework supporting these operators, which can be used to solve common query reasoning problems such as satisfiability and containment of queries in exponential time.
    IJCAI 2011, Proceedings of the 22nd International Joint Conference on Artificial Intelligence, Barcelona, Catalonia, Spain, July 16-22, 2011; 01/2011

Full-text (3 Sources)

Available from
May 23, 2014