Contextual array grammars and array P systems

Contextual array grammars, with selectors not having empty cells, are considered. A P system model, called contextual array P system , that makes use of array objects and contextual array rules, is introduced and its generative power for the description of picture arrays is examined. A main result of the paper is that there is a proper infinite hierarchy with respect to the classes of languages described by contextual array P systems. Such a hierarchy holds as well in the case when the selector is also endowed with the #−sensing ability.