Showing papers on "Chomsky hierarchy published in 1979"

Introduction to Automata Theory, Languages, and Computation

Abstract: This book is a rigorous exposition of formal languages and models of computation, with an introduction to computational complexity. The authors present the theory in a concise and straightforward manner, with an eye out for the practical applications. Exercises at the end of each chapter, including some that have been solved, help readers confirm and enhance their understanding of the material. This book is appropriate for upper-level computer science undergraduates who are comfortable with mathematical arguments.

On the generative capacity of conditional grammars

Abstract: A conditional grammar is a Chomsky grammar with languages associated to its rules such that each rule is applicable only to words in the corresponding language. In this paper the generative capacity of type 0, 1, 2, 2 — λ , 3 grammars with associated type 0, 1, 2, 3 languages will be characterized in terms of the Chomsky hierarchy. We shall prove that the generative capacity of context-free and of regular grammars is increased in this way, while for type-0 and type-1 grammars the generative capacity is not modified. Two other variants of these grammars are shown to be equivalent with them.

Formal languages: Origins and directions

Abstract: Origins of the theory of formal languages and automata are surveyed starting from 1936 with the work of Turing and Post. Special attention is given to the machine translation projects of the 1950s and early 1960s and associated work in mathematical linguistics. The development of the Chomsky hierarchy of grammars, machines, and languages from 1956 to 1964 is traced. It is observed that the same important ideas emerged independently for the automatic analysis and translation of both natural and artificial languages. Since 1964, formal language theory is part of theoretical computer science. A few of the directions since 1964 are considered: restrictions and extensions of context-free grammars and pushdown store automata, unifying frameworks, and complexity questions.

DAGs and Chomsky Hierarchy (Extended Abstract)

Abstract: Language and Syntax • As before, we say that a language is a set of strings/words; each string is a finite sequence of symbols taken from a finite alphabet. • For parsing, the strings are source programs, the symbols are lexical tokens, and the alphabet is the set of token types returned by the lexical analyzer. • Some strings are recognized as correct, well-formed strings of the language and some not. • The grammar or syntax of the language defines the set of well-formed strings.