Presented before ISO/IEC JTC1/SC7/WG42, Meeting #42, on 11 November 2024, in support of the architecture/design distinction in ISO/IEC/IEEE 42024, Architecture fundamentals.

The talk sets out the Locality Criterion: a statement is local if and only if it is preserved under expansion. Architectural statements are exactly the non-local ones — those a program can violate by growing. Worked examples separate architectural statements from detailed design, and the criterion is applied to Garlan, Allen and Ockerbloom’s Architectural Mismatch (1995) to make non-local assumptions explicit.

Based on A. H. Eden and R. Kazman, “Architecture, Design, Implementation”, ICSE 2003, pp. 149–159.