Book ChapterDOI
Word Problem for Thue Systems with a Few Relations
Yuri Matiyasevich
- pp 39-53
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The history of investigations on the word problem for Thue systems is presented with the emphasis on undecidable systems with a few relations, and the best known result, a Thue system with only three relations and undECidable word problem is presented.Abstract:
The history of investigations on the word problem for Thue systems is presented with the emphasis on undecidable systems with a few relations. The best known result, a Thue system with only three relations and undecidable word problem, is presented with details. Bibl. 43 items.read more
Citations
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Proceedings ArticleDOI
Decision problems for semi-Thue systems with a few rules
TL;DR: It is shown that the the Termination Problem, the U-Termination problem, the Accessibility Problem and the Common-Descendant Problem are undecidable for 3 rules semi-Thue systems.
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Finitary PCF is not decidable
TL;DR: It is shown that the ordering of finitary PCF is in fact undecidable, which places limits on how explicit a representation of the fully abstract model can be.
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Overview of complexity and decidability results for three classes of elementary nonlinear systems
TL;DR: It has become increasingly apparent this last decade that many problems in systems and control are NP-hard and, in some cases, undecidable.
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Some Open Problems in Decidability of Brick (Labelled Polyomino) Codes
TL;DR: The codicity problem is decidable for sets with keys of size n when n = 1 and, under obvious constraints, for every n, and it is proved that it is undecidable in the general case of sets with Key n, when n≥ 6.
References
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Journal ArticleDOI
A variant of a recursively unsolvable problem
TL;DR: In this article, the correspondence decision problem is defined as the problem of determining for an arbitrary finite set (gu g{), (g2, g2), • • •, (gM, gi) of pairs of corresponding non-null strings on a, b whether there is a solution in w, iu ii, • •• •, in of equation
Journal ArticleDOI
Recursive Unsolvability of a Problem of Thue
TL;DR: Thue's problem is the problem of determining for arbitrarily given strings A, B on al, whether, or no, A and B are equivalent, and this problem is more readily placed if it is restated in terms of a special form of the canonical systems of [3].
Journal ArticleDOI
Subgroups of Finitely Presented Groups
TL;DR: The main theorem of as discussed by the authors states that a finitely generated group can be embedded in a finite presented group if and only if it has a recursively enumerable set of defining relations.