We investigate the generative power of cooperating distributed grammar
systems (CDGSs), if the cooperation protocol is based on the level of
competence on the underlying sentential form. A component is said to be
=*k*-competent
( <=*k*-,
>=*k*-competent, resp.) on a
sentential form if it is able to rewrite exactly
*k*
(at most *k*, at least
*k*, resp.) different nonterminals
appearing in that string. In most cases CDGSs working according to the above described cooperation strategy turn out to give new characterizations
of the language families based on random context conditions, namely random context (context-free) languages and the biologically motivated family of
languages generated by ET0L systems with random context. Thus, the results
presented in this paper can shed new light on some longstanding open
problems in the theory of regulated rewriting.