History reminds us that a mathematical proof does not 'create' an equivalence; it only 'reveals' it. We do not generate a fundamental reality with a document; we formalize it. Thinking that a proof establishes the existence of a relationship is like believing that a sales deed creates a house instead of simply attesting to its ownership. The equivalence between sensitivities based on fixed points and KKT conditions existed before the demonstration, which only made it evident. For example, specific market conditions can make a theoretical equivalence unusable in practice, invalidating the idea that the proof alone suffices to establish its operational existence.