ISOA–SSCL: A Control–Regime Framework with Executable Demonstrator (v1.0)

Contemporary chemistry assumes that identical reaction systems, governed by the same equations and initial conditions, should converge to identical outcomes. Yet across catalysis, reaction kinetics, polymerization, and complex reaction networks, experimentally stable but divergent yields, pathways, and steady states are routinely observed — often treated as noise, irreproducibility, or uncontrolled variables. This work introduces a regime-dependent control framework for chemical systems, demonstrating that such divergence can arise structurally, without parameter tuning, stochastic forcing, or model failure. By reframing reaction dynamics as operating across distinct control regimes, the framework explains how identical chemical systems may converge to different, internally consistent stable outcomes. An executable Python demonstrator is provided to illustrate regime separation and transition in minimal reaction-like systems. The framework is model-agnostic, dataset-independent, and designed to operate as a post hoc interpretive layer compatible with existing chemical theories and experimental pipelines. Importantly, this regime-based structure naturally extends beyond chemistry. A direct conceptual bridge to biological regulatory systems is provided (see related work on regime-dependent physiological responses), highlighting the continuity between chemical reaction control and biological regulation. This work is intended for researchers in chemical kinetics, catalysis, systems chemistry, and interdisciplinary control theory who seek structural explanations for persistent divergence — not incremental recalibration.