P-selective sets, tally languages, and the behavior of polynomial time reducibilities on NP

Preliminary report
  • Alan L. Selman
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 71)


The notion of p-selective sets, and tally languages, are used to study polynomial time reducibilities on NP. P-selectivity has the property that a set A belongs to the class P if and only if both Ā ≤ m P A and A is p-selective. We prove that for every tally language set in NP there exists a polynomial time equivalent set in NP that is p-selective. From this result it follows that if NEXT ≠ DEXT, then polynomial time Turing and many-one reducibilities differ on NP.


Polynomial Time Turing Machine Conjunctive Normal Form Polynomial Time Reducibility Polynomial Time Computable Function 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1979

Authors and Affiliations

  • Alan L. Selman
    • 1
  1. 1.Computer Science DepartmentIowa State UniversityAmes

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