Editing Space hierarchy theorem (section)

==== Proof ====

[[Savitch's theorem]] shows that <math>\mathsf{NL} \subseteq \mathsf{SPACE}(\log^2n)</math>, while the space hierarchy theorem shows that <math>\mathsf{SPACE}(\log^2n) \subsetneq \mathsf{SPACE}(n)</math>. The result is this corollary along with the fact that TQBF &notin; NL
since TQBF is PSPACE-complete.

This could also be proven using the non-deterministic space hierarchy theorem to show that NL ⊊ NPSPACE, and using Savitch's theorem to show that PSPACE = NPSPACE.