Results 11 to 20 of about 290,995 (337)
Learning Cover Context-Free Grammars from Structural Data [PDF]
Scientific Annals of Computer Science, 2014 We consider the problem of learning an unknown context-free gram- mar from its structural descriptions with depth at most ℓ. The structural descriptions of the context-free grammar are its unlabelled derivation trees. The goal is to learn a cover context-
M. Marin, G. Istrate
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Reduction of context-free grammars [PDF]
Information and Control, 1970 This paper is concerned with the following problem: Given a context-free grammar G, find a context-free grammar with the fewest nonterminal symbols or with the fewest rules that is equivalent to G. A reduction procedure is presented for finding such a reduced context-free grammar that is structurally equivalent to a given G.
Tadao Kasami, Kenichi Taniguchi
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Complexity of Problems of Commutative Grammars [PDF]
Logical Methods in Computer Science, 2015 We consider commutative regular and context-free grammars, or, in other words, Parikh images of regular and context-free languages. By using linear algebra and a branching analog of the classic Euler theorem, we show that, under an assumption that the ...
Eryk Kopczynski
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Restricted Global Grammar Constraints [PDF]
arXiv, 2009 We investigate the global GRAMMAR constraint over restricted classes of context free grammars like deterministic and unambiguous context-free grammars. We show that detecting disentailment for the GRAMMAR constraint in these cases is as hard as parsing an unrestricted context free grammar.We also consider the class of linear grammars and give a ...
Katsirelos, George +3 more
arxiv +6 more sources
A universal context-free grammar [PDF]
Information and Control, 1975 In this report we show that, for each alphabet Σ, there exists a context-free grammar G which satisfies the property that for each context-free language L ⊆ Σ* a regular control set C can be found such that LC(G) = L.
Kasai, Takumi
openaire +3 more sources
Formal Properties of XML Grammars and Languages [PDF]
arXiv, 2000 XML documents are described by a document type definition (DTD). An XML-grammar is a formal grammar that captures the syntactic features of a DTD. We investigate properties of this family of grammars. We show that every XML-language basically has a unique XML-grammar.
Berstel, Jean, Boasson, Luc
arxiv +3 more sources
Undecidable problems concerning densities of languages [PDF]
Discrete Mathematics & Theoretical Computer Science, 2005 In this paper we prove that the question whether a language presented by a context free grammar has density, is undecidable. Moreover we show that there is no algorithm which, given two unambiguous context free grammars on input, decides whether the ...
Jakub Kozik
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Mathematics, 2022 The limitations of traditional parsing architecture are well known. Even when paired with parsing methods that accept all context-free grammars (CFGs), the resulting combination for any given CFG accepts only a limited subset of corresponding character ...
Žiga Leber +3 more
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A Context-Free Grammar Associated with Fibonacci and Lucas Sequences
Journal of Mathematics, 2023 We introduce a context-free grammar G=s⟶s+d,d⟶s to generate Fibonacci and Lucas sequences. By applying the grammar G, we give a grammatical proof of the Binet formula.
Harold Ruilong Yang
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Reduced social attention in autism is magnified by perceptual load in naturalistic environments
Autism Research, Volume 15, Issue 12, Page 2310-2323, December 2022., 2022 Abstract Individuals with autism spectrum conditions (ASC) describe differences in both social cognition and sensory processing, but little is known about the causal relationship between these disparate functional domains. In the present study, we sought to understand how a core characteristic of autism—reduced social attention—is impacted by the ...
Amanda J. Haskins +5 more
wiley +1 more source