Algebra and Logic

, Volume 42, Issue 4, pp 232–236

Necessary Isomorphism Conditions for Rogers Semilattices of Finite Partially Ordered Sets

  • Yu. L. Ershov


We establish a condition that is necessary for Rogers semilattices of computable numberings of finite families of computably enumerable sets to be isomorphic.

computable numbering computably enumerable set Rogers semilattice 


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  1. 1.
    Yu. L. Ershov, Numbering Theory [in Russian], Nauka, Moscow (1977).Google Scholar
  2. 2.
    S. D. Denisov, “The structure of an upper semilattice of recursively enumerable m-degrees and related problems. 1,” Algebra Logika, 17, No. 6, 643–683 (1978).Google Scholar

Copyright information

© Plenum Publishing Corporation 2003

Authors and Affiliations

  • Yu. L. Ershov
    • 1
  1. 1.NovosibirskRussia

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