Probabilistic grammars and languages

This work is a study of three areas in the theory of probabilistic grammars and languages. First, the relationship of branching processes to probabilistic context-free grammars is investigated. Second, a method is given for finding probabilities of certain strings in context-free languages given "regular-like" expressions representing the languages. Finally, it is shown that there is no natural way of extending Parikh's Theorem to a probabilistic version.