Structural Properties of Certain Picture Grammars
نویسندگان
چکیده
Based on the notions of locality and recognizability for n-dimensional languages ndimensionally colorable 1-dimensional languages are introduced. It is shown: A language L is in NP if and only if L is n-dimensionally colorable for some n. An analogous characterization in terms of deterministic n-dimensional colorability is obtained for P. The addition of one unbounded dimension for coloring leads to a characterization of PSPACE.
منابع مشابه
Comparison results of 2D Monogenic Pure Context Free Picture Grammars with other relating models
Picture languages generated by array grammars or accepted by array automata have been studied by researchers and various models have been proposed in the literature, motivated by problems arising in the framework of syntactic methods of pattern recognition and image processing. The notion of Pure 2D Picture Grammars, generating rectangular picture arrays of symbols is already there in the liter...
متن کاملPure 2D picture grammars and languages
A new syntactic model, called pure 2D context-free grammar (P2DCFG), is introduced based on the notion of pure context-free string grammar. The rectangular picture generative power of this 2D grammar model is investigated. Certain closure properties are obtained. An analogue of this 2D grammar model called pure 2D hexagonal context-free grammar (P2DHCFG) is also considered to generate hexagonal...
متن کاملTile rewriting grammars and picture languages
Tile Rewriting Grammars (TRG) are a new model for defining picture languages. A rewriting rule changes a homogeneous rectangular subpicture into a isometric one tiled with specified tiles. Derivation and language generation with TRG rules are similar to contextfree grammars. A normal form and some closure properties are presented. We prove this model has greater generative capacity than the Til...
متن کاملTwo-dimensional Context-free Grammars
We present a generalization of context-free grammars to twodimensions and define picture languages generated by these grammars. We examine some properties of the formed class and we describe how these languages can be recognized by two-dimensional forgetting au-
متن کاملStructural Priming Effects on EFL Production of Passive Structures
This study investigates the role structural priming plays in production of passive structures among Iranian EFL learners. In order to answer the research question, which asked whether structural priming effects result in an increase in the production of the target structure (i.e., passive structures), 60 Iranian EFL learners participated in the study. After taking the placement test, they were ...
متن کامل