提高硬度结果

摘要：

本文介绍了一种技术证明问题的多项式层次或PSPACE的类很难。这种技术的基本原理是，一些问题的限制能够模拟存在或全称量词。如果是这种情况，从量化布尔公式（QBF）到这些限制的约简可以被转换为从在前面具有多个量词的QBF的约简。这意味着在多项式层次中的n级的问题的硬度的证明可以被分成n个单独的证明，这可能比直接示出从一类QBF到所考虑的问题的简化的证明更简单。

英文摘要：

This article presents a technique for proving problems hard for classes of the polynomial hierarchy or for PSPACE. The rationale of this technique is that some problem restrictions are able to simulate existential or universal quantifiers. If this is the case, reductions from Quantified Boolean Formulae (QBF) to these restrictions can be transformed into reductions from QBFs having one more quantifier in the front. This means that a proof of hardness of a problem at level n in the polynomial hierarchy can be split into n separate proofs, which may be simpler than a proof directly showing a reduction from a class of QBFs to the considered problem.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。