The claim states a fundamental microeconomic principle: a firm that maximizes profit must necessarily operate at minimum cost for whatever output level it chooses (since failing to minimize cost for a given output means profits could be higher, contradicting profit maximization). This applies regardless of market structure (pure competition or monopoly). None of the retrieved papers specifically address or test this foundational microeconomic theorem as their primary empirical or theoretical thesis; instead, they discuss hospital scale efficiency, agricultural cooperative optimization, supply chain inventory, and corporate governance. Because this is a definitional mathematical result of firm theory and everyday microeconomic observation, it falls under COMMON_KNOWLEDGE.