From the Change Management Hypothesis to the Independent Variation Principle

The Change Management Hypothesis (CMH) postulates that the primary purpose of modularization is to minimize the economic cost of change over the system’s lifetime; for systems whose primary economic concern is ongoing evolution, CMH is the candidate foundational objective. The Independent Variation Principle (IVP) is the software-specific principle that constrains elements and their grouping by change-driver assignment. This paper isolates the sufficient steps that carry CMH to IVP, with no motivating, applicative, or supplementary material. Seven load-bearing steps are presented: the CMH postulate; the system tuple; cost factorization; the model-fidelity premise; structural exhaustion with monotonicity properties M1–M4; the CMH-compatible cost-model class; and the four conditions with their completeness theorem. Specialized to software, the four conditions — admissibility, Element Form, Separation, Unification — are exactly the IVP axioms. Within the CMH-compatible cost-model class, under model fidelity, when 𝐸 satisfies Admissibility and Element Form, and in the regime where contamination penalties dominate access savings, the Γ-equivalence partition is the unique CMH optimum up to coarsening ties. Below that regime, CMH itself prescribes a coarser partition; the derivation makes the divergence threshold explicit. A single worked example instantiates the whole chain on a three-element system.