Results 11 to 20 of about 283,476 (338)
Analyzing ambiguity of context-free grammars [PDF]
BRICS Report Series, 2009 <p>It has been known since 1962 that the ambiguity problem for context-free grammars is undecidable. Ambiguity in context-free grammars is a recurring problem in language design and parser generation, as well as in applications where grammars are used as models of real-world physical structures.
Claus Brabrand +2 more
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On Müller context-free grammars
Theoretical Computer Science, 2011 AbstractWe define context-free grammars with Müller acceptance condition that generate languages of countable words. We establish several elementary properties of the class of Müller context-free languages including closure properties and others. We show that every Müller context-free grammar can be transformed into a normal form grammar in polynomial ...
Zoltán Ésik, Szabolcs Iván
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Context-Free Grammars with Storage [PDF]
arXiv, 2014 Context-free S grammars are introduced, for arbitrary (storage) type S, as a uniform framework for recursion-based grammars, automata, and transducers, viewed as programs. To each occurrence of a nonterminal of a context-free S grammar an object of type S is associated, that can be acted upon by tests and operations, as indicated in the rules of the ...
arxiv +3 more sources
Split-Based Algorithm for Weighted Context-Free Grammar Induction
Applied Sciences, 2021 The split-based method in a weighted context-free grammar (WCFG) induction was formalised and verified on a comprehensive set of context-free languages. WCFG is learned using a novel grammatical inference method. The proposed method learns WCFG from both
Mateusz Gabor +2 more
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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
Grammar Compression with Probabilistic Context-Free Grammar [PDF]
2020 Data Compression Conference (DCC), 2020 We propose a new approach for universal lossless text compression, based on grammar compression. In the literature, a target string $T$ has been compressed as a context-free grammar $G$ in Chomsky normal form satisfying $L(G) = \{T\}$. Such a grammar is often called a \emph{straight-line program} (SLP).
Hiroaki Naganuma +4 more
openaire +3 more sources
Educators' positive practices with refugee pupils at two schools in England
British Educational Research Journal, Volume 48, Issue 6, Page 1125-1144, December 2022., 2022 Abstract Extensive evidence indicates that education is an integral part of the settling in process for refugee and asylum‐seeking children. Furthermore, it has been suggested that positive teaching practice with refugee pupils should be asset‐based and holistic in nature. The present study examines educators' positive practices with refugee pupils and
Caitlin M. Prentice
wiley +1 more source