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Towards Better Separation between Deterministic and Randomized Query Complexity

Computational Complexity 2015-06-25 v2

Abstract

We show that there exists a Boolean function FF which observes the following separations among deterministic query complexity (D(F))(D(F)), randomized zero error query complexity (R0(F))(R_0(F)) and randomized one-sided error query complexity (R1(F))(R_1(F)): R1(F)=O~(D(F))R_1(F) = \widetilde{O}(\sqrt{D(F)}) and R0(F)=O~(D(F))3/4R_0(F)=\widetilde{O}(D(F))^{3/4}. This refutes the conjecture made by Saks and Wigderson that for any Boolean function ff, R0(f)=Ω(D(f))0.753..R_0(f)=\Omega({D(f)})^{0.753..}. This also shows widest separation between R1(f)R_1(f) and D(f)D(f) for any Boolean function. The function FF was defined by G{\"{o}}{\"{o}}s, Pitassi and Watson who studied it for showing a separation between deterministic decision tree complexity and unambiguous non-deterministic decision tree complexity. Independently of us, Ambainis et al proved that different variants of the function FF certify optimal (quadratic) separation between D(f)D(f) and R0(f)R_0(f), and polynomial separation between R0(f)R_0(f) and R1(f)R_1(f). Viewed as separation results, our results are subsumed by those of Ambainis et al. However, while the functions considerd in the work of Ambainis et al are different variants of FF, we work with the original function FF itself.

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Cite

@article{arxiv.1506.06399,
  title  = {Towards Better Separation between Deterministic and Randomized Query Complexity},
  author = {Sagnik Mukhopadhyay and Swagato Sanyal},
  journal= {arXiv preprint arXiv:1506.06399},
  year   = {2015}
}

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R2 v1 2026-06-22T09:57:32.243Z