FPF Reference

    SYSTEM-DELIMITATION - Decide which entities are parts of the system and which relations only cross its boundary

    Preface node heading:system-delimitation-decide-which-entities-are-parts-of-the-system-and-which-relations-only-cross-its-boundary:662

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    This is generated FPF reference text from the specification preface or supporting sections. It helps interpret FPF; it is not FPF Reference product documentation.

    Methodology

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    Content

    • Situation and question. One exact system has already been recognized, and an aggregation or delimitation decision depends on which entities are its parts, which direct world facts and use-relative selection make an entity included or excluded for this decision, and which exact relations merely cross that boundary. If system recognition is still unresolved, stop at that A.1 blocker or use SYSTEM-RECOGNITION first.
    • First route. Open B.1.2 as the coordinator. Keep the exact system, its environment, an actual containing system, project system-of-interest designation, and any claim or model-use qualification separate. Here environment is only Plain shorthand for the exact external referents and crossing relations made relevant by the stated delimitation and use.
    • Template A — parts and assembly. Use A.14, the exact part-relation specialization, and C.13 to return exact obtaining part relations and the assembly they support—or the exact missing participant, predicate, relation owner, or assembly basis.
    • Template B — facts and boundary-use selection. Recover system identity under A.1, obtaining parthood and assembly under A.14, its exact specialization, and C.13, and every external crossing under its direct relation owner. If those facts answer the part-or-crossing question, stop there. If the named use additionally makes a choice among already available boundary readings current, C.11 returns the exact ChoiceResult; after architecture synthesis, C.32.PAD may return the exact ArchitectureDecisionRelation@Project for the named project Work. A different choice branch passes only after its admitted direct decision owner and result are named; otherwise stop with the missing-governor blocker. If later reliance needs a durable statement, identify a separate C.2.1 claim-bearing episteme whose claim content names the inclusion, exclusion, identity-preservation, and use basis, plus the exact ChoiceResult, ArchitectureDecisionRelation@Project, or other admitted direct result that makes the statement current. The episteme, diagram boundary, and Context label create none of the world facts.
    • Template C — boundary crossing. Return one exact supply, flow, coupling, control, measurement, evidence, publication, transformation, commitment, or other relation occurrence under its direct owner, with exact participant bindings—or the exact missing governor or obtaining fact. Importance, interaction, change, and spatial surrounding do not make the external participant a part.
    • Template D — selected organization. Only when the joint organization changes the decision, use A.22 to select one non-agentive U.Structure with exact independently identified constituents, exact selected obtaining relation occurrences, exact constraints as applied, and one named selection-use frame. The structure creates none of the parts, crossings, characteristics, descriptions, evidence, or decisions.
    • Boundaries. Stop at the smallest exact part, assembly, boundary-use choice or claim, crossing, or selected-structure result that answers the named decision. Return when system identity, part predicate, assembly, inclusion or exclusion basis, direct decision or selection relation, crossing occurrence, selected constraint, or use frame changes. Architecture, function/bearer allocation, characteristics, evidence, descriptions, and representations remain with their direct owners.
    • Result test. Name the already recognized system, the aggregation or delimitation decision, the exact direct result and governor, and the concrete action or stop it supports. B.1.2 coordinates those results but returns no omnibus aggregation, delimitation, crossing, compatibility, or system-context object.
    • Public coarsening. “System delimitation” restores to the exact part-and-assembly, boundary-use choice or claim, crossing-relation, selected-structure, or blocker branch for one already recognized system.

    Last Updated: 2026-07-30 — upstream FPF commit 308edacf (github.com/ailev/FPF)