Accession Number : AD0660886

Title :   NEW PROOFS OF OLD THEOREMS IN LOGIC AND FORMAL LINGUISTICS,

Corporate Author : CARNEGIE INST OF TECH PITTSBURGH PA

Personal Author(s) : Floyd,Robert W.

Report Date : NOV 1966

Pagination or Media Count : 19

Abstract : Theorem 1 constructs, from any word problem in a semi-Thue system, an equivalent Post correspondence problem, showing the undecidability of the general Post correspondence problem. Theorem 2 constructs, from any Post correspondence problem, a minimal linear grammar which is ambiguous exactly if the Post correspondence problem has a solution, showing the undecidability of the general ambiguity problem. (Other standard undecidability results on phrase structure grammars are implied.) Theorem 3 constructs, from any word problem in a semi-Thue system, an ambiguity problem, combining the results of Theorem 1 and 2 by more direct means. No new results are presented, but standard proofs were shortened and constructions eliminated, combined, or simplified. (Author)

Descriptors :   (*LINGUISTICS, THEOREMS), GRAMMARS

Subject Categories : Linguistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE