文摘
This paper characterizes alternation trading-based proofs that the Boolean satisfiability problem is not in the time- and space-bounded class DTISP\({(n^c,n^\epsilon)}\), for various values c <?2 and \({\epsilon < 1}\). We characterize exactly what can be proved in the \({\epsilon = 0}\) case with currently known methods and prove the conjecture of Williams that \({c=2\cos(\pi/7)}\) is optimal for this. For time–space trade-offs and lower bounds on satisfiability, we give a theoretical and computational analysis of the alternation trading proofs for \({0 < \epsilon < 1}\).