Results 281 to 290 of about 318,670 (335)

Generalized context‐free grammars and multiple context‐free grammars

Systems and Computers in Japan, 1989
AbstractIt is shown that the class of languages generated by generalized context‐free grammars (gcfg's) introduced by Pollard is exactly the class of recursively enumerable sets. Next, a subclass of gcfg's called multiple context‐free grammars (mcfg's) is introduced and it is shown that the class of languages generated by mcfg's properly contains the ...
Tadao Kasami, Hiroyuki Seki, Mamoru Fujii   +2 more
openaire   +1 more source

Indexed Grammars—An Extension of Context-Free Grammars

Journal of the ACM, 1967
A new type of grammar for generating formal languages, called an indexed grammar, is presented. An indexed grammar is an extension of a context-free grammar, and the class of languages generated by indexed grammars has closure properties and decidability results similar to those for context-free languages.
openaire   +1 more source

Pullback Grammars Are Context-Free

2008
Following earlier work on pullback rewriting, we describe here the notion of graph grammar relevant to our formalism. We then show that pullback grammars are context-free and provide a surprising example, namely the context-free generation of square grids.
Ly, Olivier, Chen, Rui, Bauderon, Michel
openaire   +2 more sources

Context-Free Categorical Grammars

2009
We define generic categorical notions of rewriting and grammar, using two basic operations, pullback and pushout, and show that these categorical grammars are intrinsically context-free in the sense of Courcelle. We then specialise to various settings, including classical word grammars, hyperedge replacement grammars or node-replacement grammars.
Ly, Olivier, Bauderon, Michel, Chen, Rui
openaire   +2 more sources

On a Construction of Context-free Grammars

Fundamenta Informaticae, 2000
The grammatical inference problem is solved for the class of context-free languages. A context-free language is supposed to be given by means of all its strings. Considering all strings of length bounded by k, context-free grammars G_{j,k} with 1≤j<k are constructed. A~continual increasing of the index~$k$ leads to an~infinite sequence (G_{j,k})_{j&
openaire   +2 more sources

Predictors of Context-Free Grammars

SIAM Journal on Computing, 1980
A predictor of a context-free grammar G is a substring of a sentence in $L(G)$ which determines unambiguously the contents of the parse stack immediately before (in top-down parsing) or after (in bottom-up parsing) symbols of the predictor are processed.
openaire   +2 more sources

Modular Context-Free Grammars

Grammars, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +1 more source

Context-Free Grammars

2016
In this chapter the authors introduce context-free grammars, and they explain grammars for expressions.
Wolfgang J. Paul, Christoph Baumann, Petro Lutsyk, Sabine Schmaltz   +3 more
openaire   +1 more source

CONTEXT-FREE GRAMMARS WITH LINKED NONTERMINALS

International Journal of Foundations of Computer Science, 2007
We introduce a new type of finite copying parallel rewriting system, i. e., grammars with linked nonterminals, which extend the generative capacity of context-free grammars. They can be thought of as having sentential forms where some instances of a nonterminal may be linked.
Klein, Andreas, Kutrib, Martin
openaire   +2 more sources