Results 1  10
of
19
Generalized Probabilistic LR Parsing of Natural Language (Corpora) with UnificationBased Grammars
 COMPUTATIONAL LINGUISTICS
, 1993
"... ..."
Tree Insertion Grammar: A CubicTime, Parsable Formalism that Lexicalizes ContextFree Grammar without Changing the Trees Produced
 Computational Linguistics
, 1994
"... this paper, we study the problem of lexicalizing contextfree grammars and show that it enables faster processing. In previous attempts to take advantage of lexicalization, a variety of lexicalization procedures have been developed that convert contextfree grammars (CFGs) into equivalent lexicalize ..."
Abstract

Cited by 77 (1 self)
 Add to MetaCart
this paper, we study the problem of lexicalizing contextfree grammars and show that it enables faster processing. In previous attempts to take advantage of lexicalization, a variety of lexicalization procedures have been developed that convert contextfree grammars (CFGs) into equivalent lexicalized grammars. However, these procedures typically suffer from one or more of the following problems
Stochastic Lexicalized ContextFree Grammar
, 1993
"... Stochastic lexicalized contextfree grammar (SLCFG) is an attractive compromise between the parsing efficiency of stochastic contextfree grammar (SCFG) and the lexical sensitivity of stochastic lexicalized treeadjoining grammar (SLTAG). SLCFG is a restricted form of SLTAG that can only generate ..."
Abstract

Cited by 41 (6 self)
 Add to MetaCart
Stochastic lexicalized contextfree grammar (SLCFG) is an attractive compromise between the parsing efficiency of stochastic contextfree grammar (SCFG) and the lexical sensitivity of stochastic lexicalized treeadjoining grammar (SLTAG). SLCFG is a restricted form of SLTAG that can only generate contextfree languages and can be parsed in cubic time. However, SLCFG retains the lexical sensitivity of SLTAG and is therefore a much better basis for capturing distributional information about words than SCFG.
TreeAdjoining Grammar Parsing and Boolean Matrix Multiplication
, 1994
"... this paper we restate the TAG parsing problem as a search problem and relate it to the wellknown computational problem of Boolean matrix multiplication. This is done in such a way that time upper bounds for TAG parsing can be transferred to time upper bounds for the latter problem. More precisely, ..."
Abstract

Cited by 19 (2 self)
 Add to MetaCart
this paper we restate the TAG parsing problem as a search problem and relate it to the wellknown computational problem of Boolean matrix multiplication. This is done in such a way that time upper bounds for TAG parsing can be transferred to time upper bounds for the latter problem. More precisely, we show that any algorithm for TAG parsing that improves the O(I G II w 16) time upper bound can be converted into an algorithm for Boolean ma trix multiplication running in less than O(m 3) time, m being the order of the input * Universith di Venezia, Scienze dell'Informazione, via Torino, 155, 30172 MestreVenezia, Italy. Email: satta@moo.dsi.unive.it
Tabular Algorithms for TAG Parsing
, 1999
"... We describe several tabular algorithms for Tree Adjoining Grammax paxsing, creating a continuum from simple pure bottomup algorithms to complex predictive algorithms and showing what transformations must be applied to each one in order to obtain the next one in the continuum. ..."
Abstract

Cited by 13 (6 self)
 Add to MetaCart
We describe several tabular algorithms for Tree Adjoining Grammax paxsing, creating a continuum from simple pure bottomup algorithms to complex predictive algorithms and showing what transformations must be applied to each one in order to obtain the next one in the continuum.
Solving the correctprefix property for TAGs
 Proc. of the Fifth Meeting on Mathematics of Language, pages 124130, Schloss Dagstuhl
, 1997
"... We present a new upper bound for the computational complexity of the parsing problem for TAGs, under the constraint that input is read from left to right in a way that errors in the input are observed as soon as possible, which is called the correctprefix property. The former upper bound was O(n ..."
Abstract

Cited by 9 (0 self)
 Add to MetaCart
We present a new upper bound for the computational complexity of the parsing problem for TAGs, under the constraint that input is read from left to right in a way that errors in the input are observed as soon as possible, which is called the correctprefix property. The former upper bound was O(n 9 ), which we now improve to O(n 6 ), which is the same as that of practical parsing algorithms for TAGs without the additional constraint of the correctprefix property. Thereby we show that the correctprefix property does not require significant additional costs. 1 Introduction Traditionally, parsers and recognizers for regular and contextfree languages process input from left to right. If a syntax error occurs in the input they often detect that error immediately after its position is reached. The position of the syntax error can be defined as the last input symbol of the shortest prefix which cannot be extended to be a correct sentence in the language L. In formal notation, this p...
Lexicalized ContextFree Grammar: A CubicTime Parsable, Lexicalized Normal Form for ContextFree Grammar That Preserves Tree Structure
, 1993
"... Lexicalized contextfree grammar (LCFG) is a treebased formalism that makes use of both tree substitution and a restricted form of tree adjunction. Because of its use of adjunction, LCFG allows sufficient freedom in the way derivations can be performed that lexicalization of contextfree grammar ..."
Abstract

Cited by 7 (4 self)
 Add to MetaCart
Lexicalized contextfree grammar (LCFG) is a treebased formalism that makes use of both tree substitution and a restricted form of tree adjunction. Because of its use of adjunction, LCFG allows sufficient freedom in the way derivations can be performed that lexicalization of contextfree grammars (CFGs) is possible while preserving the structure of the trees derived by the CFGs. However, the tree adjunction permitted is sufficiently restricted that LCFGs are stringwise equivalent to CFGs and have the same cubictime worstcase complexity bounds for recognition and parsing.
A Tabular Interpretation of Bottomup Automata for TAG
, 1998
"... We present a tabular interpretation for a class of 2Stack Automata that may be used to describe bottomup parsing strategies for TAGs. The results are also useful for tabulating other existing bottomup automata models for this kind of languages. 1 Introduction Several extensions of pushdown aut ..."
Abstract

Cited by 6 (2 self)
 Add to MetaCart
We present a tabular interpretation for a class of 2Stack Automata that may be used to describe bottomup parsing strategies for TAGs. The results are also useful for tabulating other existing bottomup automata models for this kind of languages. 1 Introduction Several extensions of pushdown automata has been proposed as operational devices for describing parsing strategies for TAGs. Embedded PushDown Automata [EPDA] (VijayShanker, 1988) and 2Stack Automata [2SA] (Becker, 1994) are suitable operational devices for topdown strategies. For bottomup strategies, Bottomup EPDA [BEPDA] (Schabes and VijayShanker, 1990; Rambow, 1994) and Linear Indexed Automata [LIA] (Nederhof, 1998) have been proposed. We classify parsing strategies for TAGs w.r.t. the way adjoining is recognized and regardless of how elementary trees are traversed. In TopDown strategies, the auxiliary tree to be adjoined is predicted once the adjoining node has been reached. Examples are the Earleylike parsing...
Handling Coordination in a Tree Adjoining Grammar
, 1997
"... In this paper we show that an account for coordination can be constructed using the derivation structures in a lexicalized Tree Adjoining Grammar (LTAG). We present a notion of derivation in LTAGs that preserves the notion of fixed constituency in the LTAG lexicon while providing the flexibility nee ..."
Abstract

Cited by 3 (1 self)
 Add to MetaCart
In this paper we show that an account for coordination can be constructed using the derivation structures in a lexicalized Tree Adjoining Grammar (LTAG). We present a notion of derivation in LTAGs that preserves the notion of fixed constituency in the LTAG lexicon while providing the flexibility needed for coordination phenomena. We also discuss the construction of a practical parser for LTAGs that can handle coordination including cases of nonconstituent coordination.
Comparing tabular parsers for Tree Adjoining Grammars
 Proc. of Second International Workshop on Tabulation in Parsing and Deduction (TAPD 2000
, 2000
"... Most of tabular parsing algorithms for tree adjoining grammars has been demonstrate to attain a theoretical worstcase time complexity of O(n 6 ), where n is the length of the input string. In this work we study the experimental complexity of a variety of tabular parsers for tree adjoining gram ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
Most of tabular parsing algorithms for tree adjoining grammars has been demonstrate to attain a theoretical worstcase time complexity of O(n 6 ), where n is the length of the input string. In this work we study the experimental complexity of a variety of tabular parsers for tree adjoining grammars for the case of formal and natural language grammars. 1 Introduction Tree Adjoining Grammars (TAGs) [4] are tree rewriting systems that can be considered an extension of contextfree grammars (CFGs) where the basic structures are trees instead of productions and the main composition operation is adjoining instead of substitution. Adjoining is a more powerful operation than substitution, as a consequence: 1. The class of languages recognized by tree adjoining grammars is larger than the class recognized by contextfree grammars. 2. The time complexity of parsers increases from O(n 3 ) to O(n 6 ) and the space complexity raises from O(n 2 ) to O(n 4 ), where n is the length o...