On Time Versus Space 论文

摘要

It is shown that every deterministic multitape Turing machine of time complexity t ( n ) can be simulated by a deterministic Turing machine of tape complexity t ( n )/log t ( n ). Consequently, for tape constructable t ( n ), the class of languages recognizable by multitape Turing machines of time complexity t ( n ) is strictly contained in the class of languages recognized by Turing machines of tape complexity t ( n ). In particular the context-sensitive languages cannot be recognized in linear time by deterministic multitape Turing machines.