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.

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