A Critique of Czerwinski's "Separation of ${\rm PSPACE}$ and ${\rm EXP}$"

Abstract

Czerwinski's paper "Separation of ${\rm PSPACE}$ and ${\rm EXP}$" [Cze21] claims to prove that ${\rm PSPACE} \neq {\rm EXP}$ by showing there is no length-increasing polynomial-time reduction from a given ${\rm EXP}$-complete set to a given ${\rm PSPACE}$-complete set. However, in this critique, we show that there are fundamental flaws within the paper's approach and provide a counterexample to one of the paper's theorems, which makes the proposed proof that ${\rm PSPACE} \neq {\rm EXP}$ insufficient.