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Rewrite based Verification of XML Updates  [PDF]
Florent Jacquemard,Michael Rusinowitch
Computer Science , 2009,
Abstract: We consider problems of access control for update of XML documents. In the context of XML programming, types can be viewed as hedge automata, and static type checking amounts to verify that a program always converts valid source documents into also valid output documents. Given a set of update operations we are particularly interested by checking safety properties such as preservation of document types along any sequence of updates. We are also interested by the related policy consistency problem, that is detecting whether a sequence of authorized operations can simulate a forbidden one. We reduce these questions to type checking problems, solved by computing variants of hedge automata characterizing the set of ancestors and descendants of the initial document type for the closure of parameterized rewrite rules.
Reasoning about Functional Dependency for XML

TAN Zi-Jing,PANG Yin-Ming,SHI Bai-Le,

软件学报 , 2003,
Abstract: XML is extended with functional dependencies, which are fundamental to semantic specification. Based on DTD, tree model for XML and path expressions, definitions for node value equality and node set are given. The definition for functional dependency, logical implication and path closure are studied; the satisfiability of functional dependency in a given DTD is proved. A sound and complete set of inference rules is presented, and an algorithm to calculate closure for XML paths is proved.
Weak functional dependencies and inference rules for XML

SU Zhao,LIU Guo-hua,

计算机应用 , 2007,
Abstract: The problem of functional dependencies for Extensible Markup Language(XML) is the foundation of further research for XML database.In this paper,first,based on the definitions of Document Type Definition(DTD) and XML tree given by M.Arenas et al.,concepts of null value,incomplete tree tuple,data value partial order and minimal extended tree were proposed.Second,the definition of weak functional dependency and its satisfaction were given.Then the problem of logical implication for weak functional dependencies was studied,and a set of inference rules for XML were presented.Finally,the correctness and completeness of the set were proved.
Inference Rules of XML Strong Functional Dependency

YIN Li-feng,HAO Zhong-xiao,

计算机科学 , 2008,
Abstract: When XML document comes forth incomplete information,XML functional dependency has also important meaning for the research of key,normal form and integral restriction for XML document.XML strong functional dependency'definition based on the conception of XML schema tree under incomplete information circumstances is formalized,judging condition of XML strong functional dependency is studied.This paper gives inference rules of XML strong functional dependency and proves the soundness and completeness of infer...
Completeness and Decidability Properties for Functional Dependencies in XML  [PDF]
Millist W. Vincent,Jixue Liu
Computer Science , 2003,
Abstract: XML is of great importance in information storage and retrieval because of its recent emergence as a standard for data representation and interchange on the Internet. However XML provides little semantic content and as a result several papers have addressed the topic of how to improve the semantic expressiveness of XML. Among the most important of these approaches has been that of defining integrity constraints in XML. In a companion paper we defined strong functional dependencies in XML(XFDs). We also presented a set of axioms for reasoning about the implication of XFDs and showed that the axiom system is sound for arbitrary XFDs. In this paper we prove that the axioms are also complete for unary XFDs (XFDs with a single path on the l.h.s.). The second contribution of the paper is to prove that the implication problem for unary XFDs is decidable and to provide a linear time algorithm for it.
On Strong and Default Negation in Logic Program Updates (Extended Version)  [PDF]
Martin Slota,Martin Baláz,Jo?o Leite
Computer Science , 2014,
Abstract: Existing semantics for answer-set program updates fall into two categories: either they consider only strong negation in heads of rules, or they primarily rely on default negation in heads of rules and optionally provide support for strong negation by means of a syntactic transformation. In this paper we pinpoint the limitations of both these approaches and argue that both types of negation should be first-class citizens in the context of updates. We identify principles that plausibly constrain their interaction but are not simultaneously satisfied by any existing rule update semantics. Then we extend one of the most advanced semantics with direct support for strong negation and show that it satisfies the outlined principles as well as a variety of other desirable properties.
Extended algorithm for XML query reformulation

LI Rui,WU Kai-gui,

计算机应用 , 2009,
Abstract: Query reformulation is a key issue of the data integration,and it automatically rewrites the user's query request to the data source request directly.Recently the University of Michigan and the IBM AImaden Research Center presented a novel algorithm for constraint-based XML query reformulation,but it did not consider the problem of complex schema matching and limited the algorithm application.Based on the original query reformulation algorithm,an extended algorithm for XML query reformulation was presented,...
XTQ: A Declarative Functional XML Query Language  [PDF]
Xuhui Li,Mengchi Liu,Shanfeng Zhu,Arif Ghafoor
Computer Science , 2014,
Abstract: Various query languages have been proposed to extract and restructure information in XML documents. These languages, usually claiming to be declarative, mainly consider the conjunctive relationships among data elements. In order to present the operations where the hierarchical and the disjunctive relationships need to be considered, such as restructuring hierarchy and handling heterogeneity, the programs in these languages often exhibit a procedural style and thus the declarativeness in them is not so prominent as in conventional query languages like SQL. In this paper, we propose a declarative pattern-based functional XML query language named XML Tree Query (XTQ). XTQ adopts expressive composite patterns to present data extraction, meanwhile establishing the conjunctive, the disjunctive and the hierarchical relationships among data elements. It uses the matching terms, a composite structure of the variables bound to the matched data elements, to present a global sketch of the extracted data, and develops a deductive restructuring mechanism of matching terms to indicate data transformation, especially for restructuring hierarchy and handling heterogeneity. Based on matching terms, XTQ employs a coherent approach to function declaration and invocation to consistently extract and construct composite data structure, which integrates features of conventional functional languages and pattern-based query languages. Additionally, XTQ also supports data filtering on composite data structure such as hierarchical data, which is seldom deliberately considered in other studies. We demonstrate with various examples that XTQ can declaratively present complex XML queries which are common in practice.
The Possibility Problem for Probabilistic XML (Extended Version)  [PDF]
Antoine Amarilli
Computer Science , 2014,
Abstract: We consider the possibility problem of determining if a document is a possible world of a probabilistic document, in the setting of probabilistic XML. This basic question is a special case of query answering or tree automata evaluation, but it has specific practical uses, such as checking whether an user-provided probabilistic document outcome is possible or sufficiently likely. In this paper, we study the complexity of the possibility problem for probabilistic XML models of varying expressiveness. We show that the decision problem is often tractable in the absence of long-distance dependencies, but that its computation variant is intractable on unordered documents. We also introduce an explicit matches variant to generalize practical situations where node labels are unambiguous; this ensures tractability of the possibility problem, even under long-distance dependencies, provided event conjunctions are disallowed. Our results entirely classify the tractability boundary over all considered problem variants.
Extended flux maps on surfaces and the contracted Johnson homomorphism  [PDF]
Matthew B. Day
Mathematics , 2008,
Abstract: On a closed symplectic surface Sigma of genus two or more, we give a new construction of an extended flux map (a crossed homomorphism from the symplectomorphism group Symp(Sigma) to the cohomology group H^1(Sigma;R) that extends the flux homomorphism). This construction uses the topology of the Jacobian of the surface and a correction factor related to the Johnson homomorphism. For surfaces of genus three or more, we give another new construction of an extended flux map using hyperbolic geometry.
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