Summary: Probabilistic cooperating distributed grammar systems, introduced by K. Arthi and K. Krithivasan [\`\` Probabilistic cooperating distributed grammar systems” (submitted)], are systems of probabilistic grammars in the sense of A. Salomaa [Inf. Control 15, 529–544 (1969; Zbl 0188.03201)], i.e., a probability is associated with any transition from one rule to another rule and with any transition from one probabilistic grammar to another probabilistic grammar; a probabilistic grammar stops, if the chosen rule cannot be applied; and the generated language contains only words where the product of the transitions is larger than a certain cut-point. We study the families obtained with cut-point 0 by restricting the number of rules in a probabilistic component. We show that at most two productions in any component are sufficient to generate any recursively enumerable language. If one restricts to probabilistic components with one production in any component, then one obtains the family of deterministic ET0L systems.
For the entire collection see [Zbl 1052.00011].