Let L denote the class Logpsace and NL the class NLogspace. We use logCFL to denote the closure under logspace reductions of the set of context-free languages. We prove that NL is different from logCFL. This result implies L different from Ptime and the stronger separation NL different from Ptime.

翻译：设L表示对数空间类Logpsace，NL表示非确定型对数空间类NLogspace。我们用logCFL表示上下文无关语言集在对数空间归约下的闭包。我们证明NL与logCFL不同。该结果蕴含L与Ptime不同，以及更强的分离结果NL与Ptime不同。