Accession Number:
AD0660886
Title:
NEW PROOFS OF OLD THEOREMS IN LOGIC AND FORMAL LINGUISTICS,
Descriptive Note:
Corporate Author:
CARNEGIE INST OF TECH PITTSBURGH PA
Personal Author(s):
Report Date:
1966-11-01
Pagination or Media Count:
19.0
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:
Subject Categories:
- Linguistics