Formalization of the Distinction Between Operational Noise and Signal

This record contains the English version of a theoretical work on the distinction between operational noise and signal within the framework of Distributed Informational Determinism (DID). The paper develops a formal criterion for evaluating whether a given piece of information is relevant with respect to a specific analytical domain, rather than in absolute terms. The contribution is conceptual and formal in nature. It is intended to support discussion on trajectory-based relevance, counterfactual variation, domain-dependent analysis, and the interpretation of noise and signal in complex systems. The Italian and English records are maintained separately in order to keep their respective version histories distinct.