{\displaystyle |V(H)|^{{\mathcal {O}}(k)}} 算法中,複雜度的指數可能無法再壓低太多:若指數時間假設(英语:exponentialtimehypothesis)(ETH)為真,則不存在時間複雜度為 | V ( H ) | o ( t w ( G ) / log t w ( G
[quant-ph]. A. Kitaev and J. Watrous. Parallelization, amplification, and exponentialtime simulation of quantum interactive proof systems[永久失效連結]. Proceedings