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Recursive Unsolvability of a problem of Thue

Published online by Cambridge University Press:  12 March 2014

Emil L. Post
Emil L. Post*
Affiliation:
The City College, College of The City of New York
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Extract

Alonzo Church suggested to the writer that a certain problem of Thue [6] might be proved unsolvable by the methods of [5]. We proceed to prove the problem recursively unsolvable, that is, unsolvable in the sense of Church [1], but by a method meeting the special needs of the problem.

Thue's (general) problem is the following. Given a finite set of symbols α1, α2, …, αμ, we consider arbitrary strings (Zeichenreihen) on those symbols, that is, rows of symbols each of which is in the given set. Null strings are included.

Type
Research Article
Information
The Journal of Symbolic Logic , Volume 12 , Issue 1 , March 1947 , pp. 1 - 11
Copyright
Copyright © Association for Symbolic Logic 1947

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References

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