05-01-202605-01-2026<p>We prove that a maintenance problem on frequency-constrained maintenance jobs with a hierarchical structure is integer-factorization hard. This result holds even on simple systems with just two components to maintain. As a corollary, we provide a first hardness result for Levi et al.'s modular maintenance scheduling problem (Levi et al. 2014).</p>info:eu-repo/semantics/openAccessComputational complexityInteger-factorizationMaintenance schedulingArticle