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

Abstract

Czerwinski's paper "Separation of $\mathrm{PSPACE}$ and $\mathrm{EXP}$" [Cze21] claims to prove that $\mathrm{PSPACE}\ne \mathrm{EXP}$ by showing there is no length-increasing polynomial-time reduction from a given $\mathrm{EXP}$-complete set to a given $\mathrm{PSPACE}$-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 $\mathrm{PSPACE}\ne \mathrm{EXP}$ insufficient.