Comparing Reductions to NP-Complete Sets

John M. Hitchcock and A. Pavan

Abstract:
Under the assumption that NP does not have p-measure 0, we investigate reductions to NP-complete sets and prove the following:

  1. Adaptive reductions are more powerful than nonadaptive reductions:
    there is a problem that is Turing-complete for NP but not truth-table-complete.

  2. Strong nondeterministic reductions are more powerful than deterministic reductions:
    there is a problem that is SNP-complete for NP but not Turing-complete.

  3. Every problem that is many-one complete for NP is complete under
    length-increasing reductions that are computed by polynomial-size circuits.
The first item solves one of Lutz and Mayordomo's "Twelve Problems in Resource-Bounded Measure" (1999). We also show that every problem that is complete for NE is complete under one-to-one, length-increasing reductions that are computed by polynomial-size circuits.

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