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                                                    Recursive Unsolvability of a problem of Thue

                                                    Published online by Cambridge University Press:  12 March 2014


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

                                                    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.


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                                                    Research Article
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                                                    Copyright © Association for Symbolic Logic 1947

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                                                    This article has been cited by the following publications. This list is generated based on data provided by Crossref.

                                                    Evans, Trevor 1951. On multiplicative systems defined by generators and relations. Mathematical Proceedings of the Cambridge Philosophical Society, Vol. 47, Issue. 4, p. 637.

                                                    Kalmár, László 1952. Another proof of the Markov—Post theorem. Acta Mathematica Academiae Scientiarum Hungaricae, Vol. 3, Issue. 1-2, p. 1.

                                                    Boone, William W. 1954. Certain Simple, Unsolvable Problems of Group Theory. I1)1)Unless otherwise indicated, the results and proofs of this and subsequent related papers are as given (in somewhat more detail) in Several simple unsolvable problems of group theory related to the word problem, a doctoral dissertation accepted by Princeton University in April, 1952. The proof of the unsolvability of the quasi-MAGNUS problem was presented to a meeting of The Association for Symbolic Logic, April 28, 1951. (Abstract, Journal of Symbolic Logic, 16, 237.)Our thanks are due to Professors Alonzo Church and Roger Lyndon for their constructive suggestions regarding this dissertation; to Professor Wilhelm Magnus, for stimulating discussions regarding possible extensions.. Indagationes Mathematicae (Proceedings), Vol. 57, Issue. , p. 231.

                                                    Tamari, Dov 1955. Une contribution aux theories modernes de communication: machines de Turing et problemes de mot. Synthese, Vol. 9, Issue. 1, p. 205.

                                                    Hohn, F. E. Seshu, S. and Aufenkamp, D. D. 1957. The Theory of Nets. IEEE Transactions on Electronic Computers, Vol. EC-6, Issue. 3, p. 154.

                                                    1959. A Study in the Philosophy of Science. Vol. 25, Issue. , p. 682.

                                                    Shepherdson, J. C. and Sturgis, H. E. 1963. Computability of Recursive Functions. Journal of the ACM, Vol. 10, Issue. 2, p. 217.

                                                    Stahl, Walter R. and Goheen, Harry E. 1963. Molecular algorithms. Journal of Theoretical Biology, Vol. 5, Issue. 2, p. 266.

                                                    Richard Büchi, J. 1964. Regular canonical systems. Archiv für Mathematische Logik und Grundlagenforschung, Vol. 6, Issue. 3-4, p. 91.

                                                    Fischer, Patrick C. 1964. On formalisms for turing machines. p. 68.

                                                    Shepherdson, J. C. 1965. Machine Configuration and Word Problems of Given Degree of Unsolvability. Mathematical Logic Quarterly, Vol. 11, Issue. 2, p. 149.

                                                    Knuth, Donald E. 1965. On the translation of languages from left to right. Information and Control, Vol. 8, Issue. 6, p. 607.

                                                    FOSTER, J.M. 1966. Advances in Programming and Non-Numerical Computation. p. 83.

                                                    Yasuhara, Ann 1967. A Remark on Post Normal Systems. Journal of the ACM, Vol. 14, Issue. 1, p. 167.

                                                    Aanderaa, Stål and Fischer, Patrick C. 1967. The Solvability of the Halting Problem for 2-State Post Machines. Journal of the ACM, Vol. 14, Issue. 4, p. 677.

                                                    1967. Algebra. p. 799.

                                                    Singletary, W. E. 1967. The equivalence of some general combinatorial decision problems. Bulletin of the American Mathematical Society, Vol. 73, Issue. 3, p. 446.

                                                    Greibach, Sheila A. 1967. A note on pushdown store automata and regular systems. Proceedings of the American Mathematical Society, Vol. 18, Issue. 2, p. 263.

                                                    Cudia, Dennis F. and Singletary, Wilson E. 1968. Degrees of Unsolvability in Formal Grammars. Journal of the ACM, Vol. 15, Issue. 4, p. 680.

                                                    1968. Contributions to Mathematical Logic - Proceedings of the Logic Colloquium, Hannover 1966. Vol. 50, Issue. , p. 37.

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