In: Theoretical Computer Science 259 (1-2), pages 405-426. May 2001.
Abstract: We introduce several internally hybrid derivation modes of cooperating distributed (CD) grammar systems. External hybridizations were investigated by Mitrana and Paun: for example, some components of a CD grammar system, when enabled, have to work as long as possible ¯ they work in the so-called t-mode ¯, and some others, when enabled, perform at least k derivation steps ¯ this is the so-called k-mode. On the other hand, in an internally hybrid grammar system combining the t- and k-mode ¯ we denote this combination by (t k) ¯ each component, when enabled, has to work as long as possible, yet performing at least k derivation steps. In this paper, among other things, we show that such externally hybrid CD grammar systems with components working in the t-mode and the k-mode, can be characterized by CD grammar systems with all components working in the (t k)-mode, and these can be characterized by recurrent programmed grammars with appearance checking, or, as well, by ET0L systems with permitting random context.
Keywords: Grammar systems; Hybrid modes; Recurrent programmed grammers.