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**On random reductions from sparse sets to tally sets.**
*(English)*
Zbl 0780.68044

A set \(S\subseteq\{0,1\}^*\) is called sparse if for each natural \(n\) it contains only a polynomial number of words of length \(n\). A set \(T\subseteq \{1\}^*\) is called tally. It is shown that every sparse set \(S\) can be many-one reduced to an appropriate tally set \(T\) by a polynomial-time, randomized reduction. The proof is based on the Chinese remainder theorem. As a consequence of the main result it is proven that there exists a tally set in NP which is complete for all sparse sets in NP under polynomial randomized many-one reduction. This is a partial answer to an open problem posed by Hartmanis and Yesha in 1984.

Reviewer: K.Shvachko (Pereslavl’-Zalessky)

### MSC:

68Q15 | Complexity classes (hierarchies, relations among complexity classes, etc.) |

03D15 | Complexity of computation (including implicit computational complexity) |

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\textit{U. Schöning}, Inf. Process. Lett. 46, No. 5, 239--241 (1993; Zbl 0780.68044)

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### References:

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