ABSTRACT
The components of a PC grammar system can also be generative devices different from Chomsky grammars. Here we discuss three such variants, beginning with grammar systems having Lindenmayer systems as components. We still call them PC (grammar) systems. These systems are interesting because, on the one hand, they bring together two types of parallelism (hence a theoretical motivation), but, on the other hand, they could have some biological applications (some kinds of symbiosis, parasitism, simultaneous interrelated growing of plants and animals can probably be modelled by such systems).
