Results 241 to 250 of about 859,079 (303)

The Hardest Context-Free Language

SIAM Journal on Computing, 1973
There is a context-free language $L_0 $ such that every context-free language is an inverse homomorphic image of $L_0 $ or $L_0 - \{ e\} $. Hence the time complexity of recognition of $L_0 $ is the least upper bound for time complexity of recognition of context-free languages. A similar result holds for quasirealtime Turing machine languages.
Sheila A Greibach
exaly   +4 more sources

A context-free language for binary multinomial processing tree models

Journal of Mathematical Psychology, 2009
William H Batchelder
exaly   +2 more sources

Quotients of Context-Free Languages

Journal of the ACM, 1963
Abstract : The following results on the quotient of context free languages CFL are shown: (1) It is recursively unsolvable to determine for arbitrary CFL whether the quotient of one by another is a CFL. (2) If either set is regular and the other is a CFL, then the quotient is a CFL. (Author)
Seymour Ginsburg, Edwin H. Spanier
openaire   +2 more sources

The Edit-Distance between a Regular Language and a Context-Free Language

International Journal of Foundations of Computer Science, 2012
The edit-distance between two strings is the smallest number of operations required to transform one string into the other. The distance between languages L1and L2is the smallest edit-distance between string wi∈ Li, i = 1, 2.
Yo-Sub Han, Sang-Ki Ko, K. Salomaa
semanticscholar   +1 more source

Natural Languages and Context-Free Languages

Linguistics and Philosophy, 1982
In his 1956 paper ‘Three Models for the Description of Language’ Noam Chomsky posed an interesting open question: when we consider the human languages purely as sets of strings of words (henceforth stringsets), do they always fall within the class called context-free languages (CFL’s)?
Geoffrey K. Pullum, Gerald Gazdar
openaire   +1 more source

On Context-Free Languages

Journal of the ACM, 1966
In this report, certain properties of context-free (CF or type 2) grammars are investigated, like that of Chomsky. In particular, questions regarding structure, possible ambiguity and relationship to finite automata are considered. The following results are presented: The language generated by a ...
openaire   +1 more source

Ambiguity in context free languages

Journal of the ACM, 1966
Four principal results about ambiguity in languages (i.e., context free languages) are proved. It is first shown that the problem of determining whether an arbitrary language is inherently ambiguous is recursively unsolvable. Then a decision procedure is presented for determining whether an arbitrary bounded grammar is ambiguous.
Seymour Ginsburg, Joseph S. Ullian
openaire   +2 more sources

Context-free languages

ACM SIGACT News, 1993
This paper introduces a new level into the Chomsky of formal languages. Specifically the content-free languages are a subset of the regular languages. Content-free languages have many interesting properties.
openaire   +2 more sources

On the Growth of Context-Free Languages

J. Autom. Lang. Comb., 2008
Journal of Automata, Languages and Combinatorics, Volume 13, Number 2, 2008, 95 ...
Flavio D'Alessandro, Stefano Varricchio
openaire   +1 more source

Training-Free Long-Context Scaling of Large Language Models

International Conference on Machine Learning
The ability of Large Language Models (LLMs) to process and generate coherent text is markedly weakened when the number of input tokens exceeds their pretraining length.
Chen An, Fei Huang, Jun Zhang, Shansan Gong, Xipeng Qiu, Chang Zhou, Lingpeng Kong   +6 more
semanticscholar   +1 more source