English

A constructive proof presenting languages in $\Sigma_2^P$ that cannot be decided by circuit families of size $n^k$

Computational Complexity 2014-09-18 v2

Abstract

As far as I know, at the time that I originally devised this result (1998), this was the first constructive proof that, for any integer kk, there is a language in Σ2P\Sigma_2^P that cannot be simulated by a family of logic circuits of size nkn^k. However, this result had previously been proved non-constructively: see Cai and Watanabe [CW08] for more information on the history of this problem. This constructive proof is based upon constructing a language Γ\Gamma derived from the satisfiabiility problem, and a language Λk\Lambda_k defined by an alternating Turing machine. We show that the union of Γ\Gamma and Λk\Lambda_k cannot be simulated by circuits of size nkn^k.

Keywords

Cite

@article{arxiv.1408.6334,
  title  = {A constructive proof presenting languages in $\Sigma_2^P$ that cannot be decided by circuit families of size $n^k$},
  author = {Sunny Daniels},
  journal= {arXiv preprint arXiv:1408.6334},
  year   = {2014}
}

Comments

This is a corrected version of my previous article (of the same name) which attracted the attention of Professor Lance Fortnow at Georgia Institute of Technology ("Sixteen Years in the Making" in his Complexity Theory Blog). The original had a missing closing bracket in a footnote and a reference to the wrong step in the machine for $\Lambda_k$