Gregorczyk's hierarchy and Ackermann's function. Formal languages and classes of automata. Inherently difficult combinatorial problems. This course treats languages from an abstract point of view as defined by formal grammars and by families of abstract machines. The Chomsky hierarchy and associated automata are covered.
Emphasis is placed on context free languages.
Careful mathematical definition and proof is stressed throughout. This course does not involve programming. This course is of special interest to students interested in linguistics and in the theory of programming language compilers. Applications to searching and sorting algorithms. Complexity of parsing.