# B.3 Duality of architecture, ISO 42024 ## Published contents Contents1 Scope2 Normative references3 Terms and definitions4 Architecture concepts4.1 Overview4.2 Architecture and architecting4.3 Architecture design and solution design4.4 Architecture definition and communication4.5 Stakeholder concerns and architectural aspects4.6 Architecture viewpoints and architecture views4.7 Architecture frameworks and architecture description languages4.8 Architecture descriptions and architecture models4.9 Reference architectures and reference models4.10 Life cycle and life history4.11 Architecting precepts5 Architecting principles5.1 Introduction to the principles5.2 Principles about the purpose of an architecture5.3 Principles about the focus of an architecture5.4 Principles about architecting outcomesTerms 3.2 Architecting concepts 3.2.1 Architecture3.2.2 Architecture feature3.2.3 Architecting3.2.4 Architecting principle3.2.5 Architecture principle3.2.6 Architecture framework3.2.7 Reference architecture3.3 Entity related concepts 3.3.1 Entity of interest3.3.2 Solution entity3.3.3 Environment3.3.4 Context3.3.5 Enterprise3.3.6 System3.3.7 Aspect3.3.8 Dimension3.4 Architecture design concepts 3.4.1 Design (noun)3.4.2 Architecture design3.4.3 Architecture information package3.4.4 Engineering effort3.4.5 Solution design3.4.6 Solution information package3.4.7 Stakeholder3.4.8 Stakeholder perspective3.4.9 Concern3.5 Architecture description concepts 3.5.1 Architecture description3.5.2 Solution description3.5.3 Architecture view3.5.4 Architecture viewpoint3.5.5 Model3.5.6 Metamodel3.5.7 Reference model3.6 Entity life cycle concepts 3.6.1 Life cycle3.6.2 Life cycle phase3.6.3 Life cycle stage3.6.4 Life historyAnnexes A.1 Architecture design and solution related entitiesA.2 Architecture expressed as a set of modelsA.3 Life cycle and life history conceptsA.4 Enterprise and system conceptsA.5 Duality of architectural decomposition and architectural synthesisB.1 BackgroundB.2 Aligning architecture in designB.3 Duality of architectureB.4 Pursuit of opportunities Home / Annex B Annex B, Determining architectural significance of concepts and properties · B.3 # Duality of architecture The subclause addresses the duality of architecture. It follows A.5 on decomposition and synthesis and applies the same duality to the judgement of significance. - 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 that an architecture is both a structure and a set of properties of the whole. Significance has to be judged against both, which is why a decision can look minor in the structure and be major for a whole entity property. The annex makes that explicit. ## What to do in your practice In the significance record, require two answers: the structural effect and the whole entity effect. A decision with a small structural effect and a large property effect is architecture. A decision with a large structural effect and no property effect is often just refactoring. Record the structural effect and the property effect as two separate judgements, even when they point the same way. The discipline prevents a large refactoring from being called architecture, and it prevents a small configuration change from being missed when it alters a whole entity property. ## 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 significance record with structural and property effects. An auditor asks why a decision was treated as architecture. - The property affected and the synthesis argument. Connects the decision to the whole. - The classification outcome. Shows the judgement was made. - The review record. Shows the classification was tested. Ask your teamDoes this decision change the structure, a whole entity property, or both, and which made it significant? ## Common gaps this page catches - Significance is judged by the size of the change. - Property effects are not considered. - Refactoring is escalated as architecture. ## What to prepare before publication Add the two effect columns to the significance record. Reclassify the last ten decisions. Use the result to tune the criteria in B.1. ## Common questions What does Duality of architecture mean in ISO 42024? The subclause addresses the duality of architecture. It follows A.5 on decomposition and synthesis and applies the same duality to the judgement of significance. What evidence should we keep for B.3? The significance record with structural and property effects. The property affected and the synthesis argument. The classification outcome. ## Related units - A.5 - B.1 - B.2 - B.4 Source. ISO/IEC/IEEE DIS 42024, Annex B.3, 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 Source: https://iso-42024-revision-checker.theartofservice.com/annex-b/duality-of-architecture/