IVP
The Independent Variation Principle applied to software architecture: elements assigned to the same change driver belong in the same module; elements assigned to different drivers belong in different modules [1].
This section covers the formal theory of IVP for software — the system tuple, change drivers, the Γ-equivalence partition, unit purity and completeness, and the axioms.
1 Core theory
The theory is developed in detail in the core theory pages:
- The software system tuple — the model the principle is stated over.
- Change drivers and assignment — what a change driver is and how elements are assigned to them.
- The structural formulation of IVP — the statement of the principle and its four conditions.
- The Γ-equivalence partition — the object the principle produces.
- The partition theorem — the unique compliant module structure.
- Scope and validity conditions — the premises, preconditions, and applicability gates the results depend on.
- Consequences and application — what follows, and the six-step procedure.
2 Consequences
- How to apply IVP — the six-step process and a fully worked example.
- Software clustering — how IVP dissolves the modularisation optimization problem.
The knowledge-embodiment theorem, which connects maximal cohesion to the embodiment of domain knowledge, is a result of the cohesion theory rather than of IVP itself. It is covered under cohesion.
The formal development. The definitions, theorems, and proofs behind this page are published in:
- The Independent Variation Principle — Zenodo, 2026 — doi:10.5281/zenodo.20794332
References
[1]
Y. Loth, “The independent variation principle.” Zenodo, Jun. 2026. doi: 10.5281/zenodo.20794332.