Contextual Hypergraph Grammars - A New Approach to the Generation of Hypergraph Languages
نویسندگان
چکیده
In this paper, we introduce contextual hypergraph grammars, which generalize the total contextual string grammars. We study the position of the class of languages generated by contextual hypergraph grammars in comparison with graph languages generated by hyperedge replacement grammars and double-pushout hypergraph grammars. Moreover, several examples show the potential of the new class of grammars.
منابع مشابه
Fusion Grammars: A Novel Approach to the Generation of Graph Languages
In this paper, we introduce the notion of fusion grammars as a novel device for the generation of (hyper)graph languages. Fusion grammars are motivated by the observation that many large and complex structures can be seen as compositions of a large number of small basic pieces. A fusion grammar is a hypergraph grammar that provides the small pieces as connected components of the start hypergrap...
متن کاملAttributed Context-Free Hypergraph Grammars
The concept of context-free hypergraph grammars (cfhg grammars) has been studied extensively over the past decade. In this paper we introduce attributed context-free hypergraph grammars (acfhg grammars) as an extension of cfhg grammars. An acfhg grammar consists of an underlying context-free hypergraph grammar G 0 and an attribution which associates attributes with the nonterminal symbols of G ...
متن کاملA Comparison of Boundary Graph Grammars and Context-Free Hypergraph Grammars
Context-free hypergraph grammars and boundary graph grammars of bounded nonterminal degree have the same power, both for generating sets of graphs and for generating sets of hypergraphs. Arbitrary boundary graph grammars have more graph generating power than context-free hypergraph grammars, but they have the same hypergraph generating power. To obtain these results, several normal forms for bo...
متن کاملOn the Pixel Expansion of Hypergraph Access Structures in Visual Cryptography Schemes
In a visual cryptography scheme, a secret image is encoded into n shares, in the form of transparencies. The shares are then distributed to n participants. Qualified subsets of participants can recover the secret image by superimposing their transparencies, but non-qualified subsets of participants have no information about the secret image. Pixel expansion, which represents the number of subpi...
متن کاملParsing String Generating Hypergraph Grammars
A string generating hypergraph grammar is a hyperedge replacement grammar where the resulting language consists of string graphs i.e. hypergraphs modeling strings. With the help of these grammars, string languages like anbncn can be modeled that can not be generated by context-free grammars for strings. They are well suited to model discontinuous constituents in natural languages, i.e. constitu...
متن کامل