A. Bruggemann-Klein and D. Wood. One-unambiguous regular languages. Information and Computation, 142(2):182-206, 1998.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....function can be modified accordingly to accommodate validation check for attribute formats and values. 8. MORE XML CONTENT VALIDATION XML requires content models in element type declarations be deterministic. Bruggemann Klein and Wood further clarified the requirement as meaning 1 unambiguity [7, 8]. A regular expression is 1 unambiguous if its sequence of symbols can be recognized deterministically, with one symbol lookahead, by the corresponding nondeterministic finite state machine. For example, the content model ( b, c) b, d) is not 1 unambiguous, because given an initial b, one ....

....that is related to XML content modeling but is not necessarily from the perspective of (functional) programming languages. We list just a few here. Bruggemann Klein and Wood addressed the problem of ambiguous XML (and SGML) content models, based on theory of regular languages and finite automata [7, 8]. In particular, they showed that linear time suffices to decide whether a content model is ambiguous. It is showed that regular expressions in both star normal form and epsilon normal form are always unambiguous [9] The Glushkov automaton that corresponds to a regular expression is used for ....

Anne Brugemann-Klein and Derick Wood. One-unambiguous regular languages. Information and Computation, 140(2):182--206, 1998.

....For instance, they are a suitable representation of syntactic parses, graphic patterns, segmented images or structured documents. Sometimes, comparing families of trees is of interest. For example, a document type definition (DTD) for XML documents defines by means of a EBNF context free grammar [1] a tree language where the structural tags are represented by node labels. Even if all valid documents must comply with the DTD, it is possible that some subclasses of documents show di#erent typical patterns, that is, they can be modeled by di#erent probability distributions over the language of ....

....l) b q (k, s) b # r (l, t) # st # 3 4 Preliminary results and conclusion The model has been used to compute similarities between XML document sets of di#erent authors in the Miguel de Cervantes Digital Library . The HMMs states and probabilities were extracted from the Glushkov automata [1] of the regular expressions in the DTD and from the local element frequencies in each collection. The results reflect that some author works deviate from the average A1 A2 A3 A4 A2 0.015 A3 10 7 0.548 A4 0.043 0.311 0.059 All 0.004 0.871 0.798 0.205 Fig. 1. Similarity between di#erent ....

Anne Bruggemann-Klein and Derick Wood. One-unambiguous regular languages. Information and Computation, 142(2):182--206, 1998.

....40] These are essentially unary queries: they map a document to a set of its nodes. Extended AGs are 1 This is no loss of generality, as any regular language can be denoted by an unambiguous regular expression [9] SGML is even more restrictive as it allows only one unambiguous regular languages [10, 47]. 3 DB PoemList PoemList Poem PoemList PoemList Poem Poem VerseList VerseList Verse VerseList VerseList Verse Verse WordList WordList Word WordList WordList Word Word LetterList LetterList Letter LetterList LetterList Letter Letter a j : j z Figure 1: A ....

A. Bruggemann-Klein and Wood D. One unambiguous regular languages. Information and Computation, 140(2):229-253, 1998.

....nitions 1. INTRODUCTION An extended markup language (XML) document type definition (DTD) speci es the elements that are allowed in a document of this type. Document types are de ned by extended context free grammars in which the right hand sides of productions are unambiguous regular expressions [7]. To address some of the problems posed by XML DTDs, regular tree automata (RTA) or, equivalently, forest regular grammars (FRG) have been recently proposed for use as XML schemata[12, 18] RTA based schemata are more powerful Permission to make digital or hard copies of all or part of this work ....

....a regular expression r is 1 unambiguous if for all x; y; z 2 N (i.e. nite strings of naturals) and for all n; m 2 N xny 2 L(Er ) xmz 2 L(Er ) n 6= m 9 = r (xny) 6= r (xmy) 8) The de nition above can be formulated in an alternative fashion as follows. Theorem 1. Lemma 2. 5 in [7]) A regular expression r is 1 unambiguous if and only if the Glushkov automaton of r is deterministic. Details on how to build the Glushkov automaton for a given expression r can be found in the appendix and in [10] The next theorem supports the validity of our simpli cation process. Theorem 2. ....

A. Bruggemann-Klein and D. Wood. One-unambiguous regular languages. Information and Computation, 142(2):182-206, 1998.

....1 Introduction An Extended Markup Language (XML) document type de nition (DTD) speci es the elements that are allowed in a document of this type. Document types are de ned by extended context free grammars in which the right hand side of the productions are unambiguous regular expressions [2]. Previous work has addressed the task of identifying a DTD from examples. A common diculty in this approach is the need to nd a correct degree of generalization. Some practical tools as FRED [3] let the users customize their preferred degree of generalization. Ahonen [4, 5] builds a (k; h) ....

....regular expression r is 1 unambiguous if for all x; y; z 2 N (i.e. nite strings of naturals) and for all n; m 2 N xny 2 L(E r ) xmz 2 L(E r ) n 6= m 9 = r (xny) 6= r (xmy) 2) The de nition above can be formulated in an alternative fashion as follows. Theorem 1 (Lemma 2. 5 in [2]) A regular expression r is 1 unambiguous if and only if the Glushkov automaton of r is deterministic. Details on how to build the Glushkov automaton for a given expression r can be found in the appendix and in [10] Next theorem supports the validity of our simpli cation process. Theorem 2 Let ....

Anne Bruggemann-Klein and Derick Wood. One-unambiguous regular languages. Information and Computation, 142(2):182-206, 1998.

....to the power of top down and deterministic tree automata. This restriction is expressed by two requirements in XML Schema, which for compatibility are also adopted by XML Query: any sibling elements with the same name must have the same content, and all regular expressions must be one unambiguous [4]. Adopting these restrictions makes it easy to decide when one type is smaller than another (inclusion of languages, later written as : For deterministic and top down automata this can be determined in time quadratic in the number of states, whereas for non deterministic or bottom up automata ....

Anne Bruggemann-Klein, Derick Wood, One-Unambiguous Regular Languages, Information and Computation, 140(2): 229--253 and 142(2): 182--206, 1998.

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A. Bruggemann-Klein and D. Wood. One-unambiguous regular languages. Information and Computation, 142(2):182-206, 1998.

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A. Bruggemann-Klein and Wood D. One unambiguous regular languages. Information and Computation, 140(2):229-253, 1998.

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Anne Bruggemann-Klein and Derick Wood. One-unambiguous regular languages. Information and Computation, 142(2):182--206, 1998.

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A. Bruggemann-Klein and D. Wood. One-Unambiguous Regular Languages. Information and Computation, 142:182-206, 1998.

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