# Does there exist a language which is PSPACE-complete and regular?

Does there exist a language which is PSPACE-complete and regular? (reduction is polynomial with regard to time).

Correct answer here is "unknown". I can't prove it. Can you help me?

In fact, we can say even more: the language $\{1\}$ is PSPACE-complete if and only if P=PSPACE.
• Is it about that each regular language is in $P$ ? – Haskell Fun Aug 27 '17 at 9:16