THE AMBIGUOUS TYPE THEORY IS HEREDITARILY UNDECIDABLE
β Scribed by Andrey A. Kuzichev
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 84 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0044-3050
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β¦ Synopsis
Abstract
The ambiguous type theory ATT is introduced in [1] in order to obtain a new proof of Specker's theorem on typical ambiguity [3]. In the present paper we imbed the recursively undecidable theory TR of a single transitiveβreflexive relation in an arbitrary stratified theory T such that T β« ATT and so reduce the problem of derivability in TR to the same problem for T. From this it follows that ATT is hereditarily undecidable, i.e. ATT has no decidable subtheories.
π SIMILAR VOLUMES
The theory of one-step rewriting for a given rewrite system R and signature C is the firstorder theory of the following structure: its universe consists of all C-ground terms, and its only predicate is the relation "x rewrites to y in one step by R". The structure contains no function symbols and no