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The (generalized) Post correspondence problem with lists consisting of two words is decidable. (English) Zbl 0493.68076


MSC:

68Q45 Formal languages and automata
20F10 Word problems, other decision problems, connections with logic and automata (group-theoretic aspects)
20M05 Free semigroups, generators and relations, word problems
03D40 Word problems, etc. in computability and recursion theory
20M35 Semigroups in automata theory, linguistics, etc.

Citations:

Zbl 0485.03018
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References:

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[9] Hopcroft, J.E.; Ullman, J.D., Introduction to automata theory, languages and computation, (1979), Addison-Wesley Reading, MA · Zbl 0196.01701
[10] Karhumäki, J.; Simon, I., A note on elementary homomorphisms and the regularity of equality sets, Bull. EATCS, 9, (1979)
[11] Lecerf, Y., Recursive insolubilité de l’equation generale de diagonalisation de deux monomorphisms de monoides libres φx = ψx, C.R. acad. sci. Paris, 257, 2940-2943, (1963) · Zbl 0192.06902
[12] Post, E.L., A variant of a recursively unsolvable problem, Bull. amer. math. soc., 52, 264-268, (1946) · Zbl 0063.06329
[13] Salomaa, A., Formal languages, (1973), Academic Press New York · Zbl 0262.68025
[14] Salomaa, A., Equality sets for homomorphisms on free monoids, Acta cybernet., 4, 127-239, (1978) · Zbl 0407.68077
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