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Proceedings of the TwentyThird International Joint Conference on Artificial Intelligence Statistical Parsing with Probabilistic SymbolRefined Tree Substitution Grammars ∗
"... We present probabilistic SymbolRefined Tree Substitution Grammars (SRTSG) for statistical parsing of natural language sentences. An SRTSG is an extension of the conventional TSG model where each nonterminal symbol can be refined (subcategorized) to fit the training data. Our probabilistic model i ..."
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We present probabilistic SymbolRefined Tree Substitution Grammars (SRTSG) for statistical parsing of natural language sentences. An SRTSG is an extension of the conventional TSG model where each nonterminal symbol can be refined (subcategorized) to fit the training data. Our probabilistic model
On Inferring Linear SingleTree Languages
 Journal of HigherOrder and Symbolic Computation
, 1998
"... We consider the inferability of linear singletree languages. We are able to show that if the terminal productions of the corresponding grammars obey a simple restriction, then the languages generated are inferable from positive samples only. Moreover, we solve an open problem posed by Greibach, Shi ..."
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Cited by 1 (0 self)
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, Shi, and Simonson concerning the unambiguity of certain ultralinear STG's. Keywords: contextfree language, linear singletree language, grammatical inference, identification in the limit. 1 Introduction A contextfree grammar is a singletree grammar (STG) if every nonterminal symbol has
Generating All Permutations by ContextFree Grammars in
"... We consider contextfree grammars Gn in Greibach normal form and, particularly, in Greibach mform (m = 1,2) which generate the finite language Ln of all n! strings that are permutations of n different symbols (n ≥ 1). These grammars are investigated with respect to their descriptional complexity, i ..."
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, i.e., we determine the number of nonterminal symbols and the number of production rules of Gn as functions of n. As in the case of Chomsky normal form these descriptional complexity measures grow faster than any polynomial function.
Regular Approximation Of ContextFree Grammars Through Transformation
, 2000
"... We present an algorithm for approximating contextfree languages with regular languages. The algorithm is based on a simple transformation that applies to any contextfree grammar and guarantees that the result can be compiled into a finite automaton. The resulting grammar contains at most one new n ..."
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Cited by 36 (4 self)
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nonterminal for any nonterminal symbol of the input grammar. The result thus remains readable and if necessary modifiable. We extend the approximation algorithm to the case of weighted contextfree grammars. We also report experiments with several grammars showing that the size of the minimal deterministic
Checking the Conformance of Grammar Refinements with respect
"... Abstract—According to this paper, to refine an initial contextfree grammar supposes to devise an equivalent grammar that preserves the main syntactic structures of the initial one while making explicit other structural characteristics (e.g., associativity and priority of the operators in an express ..."
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. These relationships must be made explicit by associating core nonterminal symbols in the initial grammar with core nonterminal symbols in the grammar refinement. Once it is made, it is possible to base the heuristic test on searching regular expressions involving both terminal and core nonterminal symbols
Detecting Termination of Active Database Rules Using Symbolic Model Checking
"... One potential problem of active database applications is the nontermination of rules. Although algorithms have been proposed to detect nontermination, almost all provide a conservative estimate; that is, the algorithms detect all the potential cases of nontermination. These algorithms then lea ..."
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Cited by 2 (0 self)
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automatically detect nontermination using an existing symbolic model checker. Our approach does not require much expertise on the part of the database programmer, and can be used to detect termination cases which the conservative approaches reject as nonterminating ones. Our approach, thus, complements
Treebank grammar techniques for nonprojective dependency parsing
 In Proc. EACL
, 2009
"... An open problem in dependency parsing is the accurate and efficient treatment of nonprojective structures. We propose to attack this problem using chartparsing algorithms developed for mildly contextsensitive grammar formalisms. In this paper, we provide two key tools for this approach. First, we ..."
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Cited by 11 (1 self)
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of nonterminal symbols per production. Our second contribution is an algorithm that computes this transformation for a large, empirically relevant class of grammars. 1
Probabilistic CFG with Latent Annotations
, 2005
"... This paper defines a generative probabilistic model of parse trees, which we call PCFGLA. This model is an extension of PCFG in which nonterminal symbols are augmented with latent variables. Finegrained CFG rules are automatically induced from a parsed corpus by training a PCFGLA model using an E ..."
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Cited by 101 (1 self)
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This paper defines a generative probabilistic model of parse trees, which we call PCFGLA. This model is an extension of PCFG in which nonterminal symbols are augmented with latent variables. Finegrained CFG rules are automatically induced from a parsed corpus by training a PCFGLA model using
1.1 TopDown Rewriting and BottomUp Deduction
, 2009
"... When Chomsky first introduced the contextfree grammar (CFG), it was defined to be a restricted type of semiThue system or unrestricted rewriting system. An unrestricted rewriting system has rules of the form: α → β, where α and β are strings of terminal and nonterminal symbols. Such a rule is inte ..."
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When Chomsky first introduced the contextfree grammar (CFG), it was defined to be a restricted type of semiThue system or unrestricted rewriting system. An unrestricted rewriting system has rules of the form: α → β, where α and β are strings of terminal and nonterminal symbols. Such a rule
A systematic comparison of phrasebased, hierarchical and syntaxaugmented statistical MT
 In: Proceedings of ACLCOLING
, 2008
"... Probabilistic synchronous contextfree grammar (PSCFG) translation models define weighted transduction rules that represent translation and reordering operations via nonterminal symbols. In this work, we investigate the source of the improvements in translation quality reported when using two PSCFG ..."
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Cited by 24 (2 self)
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Probabilistic synchronous contextfree grammar (PSCFG) translation models define weighted transduction rules that represent translation and reordering operations via nonterminal symbols. In this work, we investigate the source of the improvements in translation quality reported when using two PSCFG
Results 21  30
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170