ISO 42024 Revision Checker
ISO/IEC/IEEE DIS 42024 · Enterprise, systems and software, Architecture fundamentals Stage 40.99 Planning date 15 Sep 2027, an estimate 35 terms · 20 clause areas · 9 annex sections

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Annex A, Notes on terms and concepts · A.5

Duality of architectural decomposition and architectural synthesis

The subclause is the fifth note in Annex A, on the duality of architectural decomposition and architectural synthesis. It closes the annex with the two directions of architecture work: breaking an entity into parts, and composing parts into an entity.

  • annex section, status not stated in the public preview
  • Annex section
  • ISO/IEC/IEEE DIS 42024
  • Last updated: 2026-10-21

What this unit settles

The duality is a warning against one way thinking. Decomposition is the familiar direction: break the system into components. Synthesis is the other: show how parts compose into a whole with the required properties. A firm that only decomposes can describe structure but cannot show that the whole has the properties it needs.

What to do in your practice

For each architecture, record the decomposition tree and a synthesis argument for the top three whole entity properties. The synthesis argument names the parts, the interactions and why the property emerges. Where it cannot be written, the property is assumed rather than designed. Ask the review panel to explain how a whole entity property is achieved without referring to the decomposition diagram. If the explanation is a list of components, the panel is describing structure, not architecture, and the property is being assumed rather than designed.

Who it binds

The architecture practice, as a note. The public preview does not state the annex status, so this page does not claim one.

Evidence an auditor or regulator asks for

  • The decomposition record and the synthesis argument.
    An auditor asks how the whole property is achieved, not only how the parts are organised.
  • The interactions that produce the property.
    Shows the mechanism.
  • A list of properties with no synthesis argument.
    Reveals the assumptions.
  • The review record.
    Shows the arguments were tested.
Ask your teamWhich whole entity property in this architecture has no synthesis argument, only a decomposition diagram?

Common gaps this page catches

  • Only decomposition is documented.
  • Whole entity properties are asserted without a mechanism.
  • Reviews test structure, not composition.

What to prepare before publication

Write synthesis arguments for the top three properties of one entity. Use them in the next design review. The properties without an argument become the review agenda.

Common questions

What does Duality of architectural decomposition and architectural synthesis mean in ISO 42024?
The subclause is the fifth note in Annex A, on the duality of architectural decomposition and architectural synthesis. It closes the annex with the two directions of architecture work: breaking an entity into parts, and composing parts into an entity.
What evidence should we keep for A.5?
The decomposition record and the synthesis argument. The interactions that produce the property. A list of properties with no synthesis argument.

Related units

Source. ISO/IEC/IEEE DIS 42024, Annex A.5, published contents. Open the official record. Retrieved 21 October 2026.

https://www.iso.org/obp/ui/en/#iso:std:iso-iec-ieee:42024:dis:ed-1:v1:en

ISO catalogue record 87510, the status, stage and page count.

Claim level: annex section, status not stated in the public preview. The annex title and subclause title are in the public preview. The body text is not public.

Last updated: 2026-10-21 · Markdown version · Check your practice