Joshi, A. and Y. Schabes. 1991. Tree adjoining grammars and lexicalized grammars. In M. Nivat and A. Podelski, editors, Tree automata and languages. North-Holland.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....(G) A A A A A A B B B A A A A A A A A A A A A A A A A A A A A A S t X X S X X t X Figure 2: Adjunction operation. One important characteristic of TAGs is lexicalization [JoS92]. Brie y, this means that every grammar structure (i.e. elementary tree) is anchored with a lexical item. In general, this property is not ll for CFGs grammars. Lexicalization is a good computational property because it can be proved that reduces the complexity of parsers. On the other hand, ....

Joshi, A. K. and Schabes Y. (1992) Tree Adjoining Grammars and Lexicalized Grammars. In Nivat, M (ed.), Tree Automata and Languages. North Holland.

....allow a simple notion of a tag dictionary. We solve this problem by decomposing the structure in an approach that is different from that shown above which uses context free rules. The approach uses the notion of tree rewriting as defined in the Lexicalized Tree Adjoining Grammar (LTAG) formalism (Joshi and Schabes, 1992) 1 which re 1 This is a lexicalized version of Tree Adjoining Grammar (Joshi et al. 1975; Joshi, 1985) tains the notion of lexicalization that is crucial in the success of a statistical parser while permitting a simple definition of tag dictionary. For example, the parse in Figure 1 can be ....

A. K. Joshi and Y. Schabes. 1992. Tree-adjoining grammar and lexicalized grammars. In M. Nivat and A. Podelski, editors, Tree automata and languages, pages 409--431. Elsevier Science.

....parsing grammars that are associated with functional constraints is computationally costly, the run time being exponential in the length of the input string in the worst case. Burheim (1996) proposes to replace the CFG based characterization of c structure with a tree adjoining grammar (TAG) see (Joshi and Schabes, 1991) for an overview of TAG; also see (Kameyama, 1986) for an earlier proposal to relate LFG and TAG) The elementary structures in TAG are trees; the extended domain of locality (i.e. extended over that of CFG) allows us to devise lexicalized grammars in which each elementary structure is associated ....

Joshi, A. K. and Schabes, Y. (1991). Tree-adjoining grammars and lexicalized grammars. In Nivat, M. and Podelski, A., editors, Definability and Recognizability of Sets of Trees. Elsevier.

....Our approach focuses on robust and pratical purposes. Our parsing algorithm results in more extended partial parsing when the global parsing fails and in an interesting average complexity compared with others bottom up algorithms. 1 Introduction Lexicalized Tree Adjoining Grammars (LTAG) [Joshi and Schabes, 1992] have given rise to a lot of interests for the modeling of syntax, in particular thanks to its three key properties: the principle of Extended Domain of Locality (EDL) the lexicalization and the representation of recursive phenomena using the operation of adjunction. Since these properties alow ....

Joshi, A. K. and Schabes, Y. (1992). Tree Adjoining Grammars and lexicalized grammars. In Nivat, M. and Podelski, A., editors, Tree automata and languages. Elsevier Science.

....depending on the grammar and w is the input string. As our main result we present an O(tg jwj 6 maxfg; jwjg) time algorithm, a considerable improvement over the standard LTAG parsing methods. 1. The problem We assume the reader is familiar with TAGs, LTAGs and related notions (Joshi, 1987; Joshi Schabes, 1992). Each node n in an elementary tree is associated with a selectional constraint Adj (n) representing a (possibly empty) set of elementary trees that can be adjoined at n (we treat substitution as adjunction at a childless node) We define the size of n as 1 jAdj (n)j. The size of an LTAG G, ....

JOSHI A. K. & SCHABES Y. (1992). Tree adjoining grammars and lexicalized grammars. In M. NIVAT & A. PODELSKY, Eds., Tree Automata and Languages. Amsterdam, The Netherlands: Elsevier.

.... without in (2) can be used with or without an argument and still remain an autonomously syntactical correct utterance. I try to design and implement a syntactic treatment level able to deal with this kind of problems. 2 INCOMPLETE STRUCTURES AND LTAG Lexicalized Tree Adjoining Grammars (LTAG) [7] [1] 2] is an interesting syntactic formalism for parsing natural language, 1 LORIA Henri Poincar e Nancy 1 University, BP 239, 54506 Vandoeuvre les Nancy, France. in particular thanks to its three key properties : the principle of extended domain of locality, the lexicalization and the ....

Aravind K. Joshi and Yves Schabes, `Tree Adjoining Grammars and lexicalized grammars', in Tree automata and languages, eds., Maurice Nivat and Andreas Podelski, Elsevier Science, (1992).

.... lexically specified as controlling such a local domain, as in Lexical Functional Grammar (LFG, see Bresnan 1982) Combinatory Categorial Grammar (CCG, see Steedman 1985, 1996) Head Driven Phrase Structure Grammar (HPSG, see Pollard and Sag 1987, 1994) Lexical Tree Adjoining Grammar (LTAG, see Joshi and Schabes 1992), and certain versions of the Government Binding theory (GB, see e.g. Hale and Keyser 1993 and Grimshaw 1997) The advantage of such theories lies in a closer integration of the lexicon, syntax, semantics, and phonology including intonation, as called for by Kelly (1992) Kelly and Martin (1994) ....

Joshi, Aravind and Schabes, Yves, 1992. "Tree adjoining grammars and lexicalized grammars." In M. Nivat and M. Podelski (eds.), Definability and Recognizability of Sets of Trees, Elsevier, Princeton.

....using an automaton based parser. We present algorithms for constructing automata from elementary structures, merging and minimising them, and string recognition and parse recovery with the resulting grammar. 1 Introduction It is well known that fully lexicalised grammar formalisms such as LTAG (Joshi and Schabes, 1991) are difficult to parse with efficiently. Each word in the parser s input string introduces an elementary tree into the parse table for each of its possible readings, and there is often a substantial overlap in structure between these trees. A conventional parsing algorithm (VijayShanker and ....

A. K. Joshi and Y. Schabes. 1991. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Definability and Recognizability of Sets of Trees. Elsevier.

....the derivation trees of a TAG are closely related to dependency structure (Rambow and Joshi, 1992) A salient feature of TAG is the extended domain of locality it provides for stating these dependencies. Each elementary tree can be associated with a lexical item giving us a lexicalized TAG (LTAG)(Joshi and Schabes, 1991). Properties related to the lexical item such as subcategorization, agreement, and certain types of word order variation can be expressed directly in the elementary tree (Kroch, 1987; Frank, 1992) Thus, in an LTAG all of these linguistic dependencies are expressed locally in the elementary trees ....

.... We believe that an approach towards coordination that explicitly distinguishes the dependencies from the constituency gives a better formal understanding of its representation when compared to previous approaches that use tree rewriting systems which conflate the two issues, as in (Joshi, 1990; Joshi and Schabes, 1991; Sarkar and Joshi, 1996) which have to represent sentences such as (1) with either unrooted trees or by performing structure merging on the derived tree. Other formalisms for coordination have similar motivations: however their approaches differ, e.g. CCG (Steedman, 1985; Steedman, 1997b) extends ....

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Joshi, A. and Y. Schabes. 1991. Tree adjoining grammars and lexicalized grammars.

....the same tensed surface clause. In this binding differs from the unbounded dependency between a relative pronoun and the verb that governs it. The natural explanation for bounded phenomena is that they are specified in the lexicon. Lexicalized Tree adjoining Grammars (LTAG Schabes et al. 1988, Joshi and Schabes 1992), categorial grammars (for example CCG, Steedman 1996) and various versions of ID LP grammars, are attractive formalisms. Categorial Grammar is usually presented as a system of types, such as (SnNP) NP , the type of a transitive verb in the notation used here, and ( SnNP) NP) NP , the type of a ....

.... same two alternatives presents itself when we ask ourselves how a theory of binding and control might be incorporated in a tree adjoining grammar (TAG see the other papers in this volume, and Joshi 1988, passim) Since TAGs are usually regarded as lexicalized (LTAG see Schabes et al. 1988, Joshi and Schabes 1992), the most natural move is to specify reflexivization possibilities in the lexicon, as elementary trees among the family of such trees associated with a given verb. Such a move immediately raises the question of how to capture the separation exemplified above between linear order, and dominance ....

Joshi, Aravind, and Yves Schabes. 1992. Tree-Adjoining Grammars and Lexicalized Grammars. In Definability and Recognizability of Sets of Trees, ed.

.... that the class of mildly context senstive languages which include Tree Adjoining Languages and Linear Indexed Languages , where CFL ae MCSL ae IL ae CSL Linear versions of the Schimpf Gallier tree automaton are equivalent to the tree sets of a mildly context sensitive grammar formalism (from [9]) There are a variety of results about tree acceptors and automata over infinite sequences and trees which were not considered in this paper. Thomas [20] is a survey paper which covers many important results in this area. ....

A. K. Joshi and Y. Schabes. Tree adjoining grammars and lexicalized grammars. In M. Nivat and A. Podelski, editors, Tree Automata, volume 10 of Studies in Computer Science and Artificial Intelligence, pages 409--431. North-Holland, Amsterdam, 1992.

....2 Feature Logics 5 theory) 27] their role is somewhat limited. The general flavor of such systems is becoming increasingly like other constraint based theories, though the details are quite different. In like manner, one uses feature constraints in the framework of tree adjoining grammars [38]. Although the primary focus of TAG is tree based, and purely generative, the addition of features makes the task of describing and generating actual language fragments much simpler [74] Two other significant contributions to the theory of features must be mentioned. One important influence is ....

A. K. Joshi and Yves Schabes. Tree adjoining grammars and lexicalized grammars. In Tree Automata and Languages. Elsevier, 1992.

....new grammar formalism, called D Tree Grammars (DTG) which arises from work on TreeAdjoining Grammars (TAG) Joshi et al. 1975) A salient feature of TAG is the extended domain of locality it provides. Each elementary structure can be associated with a lexical item (as in Lexicalized TAG (LTAG) (Joshi Schabes, 1991)) Properties related to the lexical item (such as subcategorization, agreement, certain types of word order variation) can be expressed within the elementary structure (Kroch, 1987; Frank, 1992) In addition, TAG remain tractable, yet their generative capacity is sufficient to account for ....

A. Joshi & Y. Schabes. 1991. Tree-adjoining grammars and lexicalized grammars. In M. Nivat & A. Podelski, eds., Definability and Recognizability of Sets of Trees.

....of related ES s we shall give two examples of optimisation of the processing of ES s through a deterministic merging of their corresponding automata, and show how different control strategies yield different optimisations. We will illustrate the approach using Lexicalized Tree Adjoining Grammars (Joshi and Schabes, 1991), but we note that the techniques described here can also be applied to other lexicalized grammar formalisms 3 . 2 Automaton based parsing of LTAG Generally speaking, parsing algorithms for LTAG have the property that a traversal is made through the nodes of elementary trees (the elementary ....

....example, the ditransitive tree given in Figure 1. A bottom up parser will initially anchor this tree on an actual ditransitive verb in the input and start its traversal at the v node. If a 1 We use the term elementary structures to mean the basic components of grammatical description. In LTAG (Joshi and Schabes, 1991), for example, the elementary structures are initial and auxiliary trees. A grammar consists of a finite set of elementary structures that are built into derived structures using the composition operations of the formalism. 2 cf. Alshawi (1996) for a similar approach. but with different ....

Joshi, Aravind K. and Yves Schabes. 1991. Tree-adjoining grammars and lexicalized grammars.

....constituent structure of language. More importantly, TAGs allow greater linguistic expressiveness. The trees associated with words can be used to encode argument and adjunct relations in various syntactic environments. This paper assumes some familiarity with the TAG formalism. Joshi, 1988) and (Joshi and Schabes, 1992) are good introductions to the formalism and its linguistic relevance. TAGs have been shown to have relations with both phrase structure grammars and dependency grammars (Rambow and Joshi, 1995) which is relevant because recent work on structured language models (Chelba et al. 1997) have used ....

A. K. Joshi and Y. Schabes. 1992. Tree-adjoining grammars and lexicalized grammars. In M. Nivat and A. Podelski, editors, Tree automata and languages, pages 409--431. Elsevier Science.

....from the parts that are specified. The formalism that Shieber and Johnson use is that of Synchronous Tree Adjoining Grammars (Shieber and Schabes 1990) I now sketch the idea briefly. The reader is referred to the original papers for details. Lexicalized) Tree Adjoining Grammar (TAG, Joshi 1985; Joshi and Schabes 1991) is a grammatical formalism where a grammar associates a finite set of trees with each lexical item and trees can combine using one of two operations: substitution and adjunction. One tree fi is substituted into another ff by simply replacing one non terminal symbol at the frontier of ff with ....

Joshi, Aravind K. and Yves Schabes. 1991. Tree-adjoining grammars and lexicalized grammars.

No context found.

Aravind K. Joshi and Yves Schabes. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. 1992. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science.

....structure. The parser extracts these structures by first associating each word in an input sentence with one or more elementary tree fragments, which are combined into a single syntax tree for the entire input sentence using the constrained operations of the Tree Adjoining Grammar formalism [17, 18]. These elementary tree fragments have argument positions for the subjects and objects of verbs, adjectives, and other predicates, which constrain the way the fragments can be combined, and which determine the predicateargument structure of the input sentence. The translator then converts this ....

Joshi, A.K., and Y. Schabes. 1996. Tree-Adjoining Grammars and Lexicalized Grammars. Handbook of Formal Languages and Automata. Springer Verlag, Berlin, eds: A. Salomaa & G. Rosenberg, 409-431.

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Aravind K. Joshi and Yves Schabes. 1991b. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Definability and Recognizability of Sets of Trees. Elsevier.

No context found.

Joshi, A. and Y. Schabes. 1991. Tree adjoining grammars and lexicalized grammars. In M. Nivat and A. Podelski, editors, Tree automata and languages. North-Holland.

No context found.

A. Joshi and Y. Shabes. Tree-adjoining grammars and lexicalized grammars. In M. Nivat and A. Podelsky, editors, De nability and Recognizability of Sets of Trees. Elsevier, 1991.

No context found.

Aravind K. Joshi and Yves Schabes. Tree adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. Tree adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Tree Automata and Languages. Elsevier Science, 1992.

No context found.

Aravind K. Joshi and Yves Schabes. 1991. Treeadjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Definability and Recognizability of Sets of Trees. Elsevier.

No context found.

Joshi, A. and Schabes, Y. (1991). Tree-Adjoining Grammars and Lexicalized Grammars. In Nivat, M., editor, Definability and Recognizability of Sets of Trees. Elsevier.

No context found.

Aravind Joshi and Yves Schabes. 1991. TreeAdjoining Grammars and Lexicalized Grammars.

No context found.

Aravind Joshi and Yves Schabes. 1991. Tree-adjoining grammars and lexicalized grammars. In Maurice Nivat and Andreas Podelski, editors, Definability and Recognizability of Sets of Trees. Elsevier.

No context found.

Joshi, A. and Schabes, Y. (1991). Tree-Adjoining Grammars and Lexicalized Grammars. In Nivat, M., editor, Definability and Recognizability of Sets of Trees. Elsevier.

No context found.

A. Joshi and Y. Schabes. Tree-Adjoining Grammars and Lexicalized Grammars. In M. Nivat, editor, Definability and Recognizability of Sets of Trees. Elsevier, 1991.

No context found.

Joshi, A. and Schabes, Y. (1991). Tree-Adjoining Grammars and Lexicalized Grammars. In Nivat, M., editor, Definability and Recognizability of Sets of Trees. Elsevier.

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