The complexity of admissible rules of Łukasiewicz logic
We investigate the computational complexity of admissibility of inference rules in infinite-valued Łukasiewicz propositional logic (Ł). It was shown in  that admissibility in Ł is checkable in PSPACE. We establish that this result is optimal, i.e. admissible rules of Ł are PSPACE-complete. In contrast, derivable rules of Ł are known to be coNP-complete.